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Data Products Special IssueIssue 1, 2013
Maintenance ExperienceEditorial Committee
Maintenance ExperienceNewsroom
Address: ZTE Plaza,No. 55, Hi-tech Road
South, ShenZhen, P.R.China
Postal code: 518057
Contact: Ning Jiating
Tel: +86-755-26776049
Fax: +86-755-26772236
Document support Email: doc@zte.com.cn
Technical support website: http://ensupport.
zte.com.cn
Maintenance ExperienceBimonthly for Data ProductsNo. 1 Issue 276, April, 2013
Director: Chen Jianzhou
Deputy Director: Zeng Li
Technical Senior Editors:Hu Jia, Tao Minjuan, Zhang Jianping,Zhu Xiaopei
Executive Editor:Zhang Fan
Maintenance Experience Editorial CommitteeZTE CorporationApril , 2012
Preface In this issue of ZTE's Maintenance Experience, we continue to pass on various field reports and resolutions that are gathered by ZTE engineers and technicians around the world. The content presented in this issue is ten cases of ZTE's Data Products.Have you examined your service policies and procedures lately? Are you confident that your people are using all the tools at their disposal? Are they trained to analyze each issue in a logical manner that provides for less downtime and maximum customer service? A close look at the cases reveals how to isolate suspected faulty or mis-configured equipment, and how to solve a problem step by step, etc. As success in commissioningand service is usually a mix of both discovery and analysis, we consider using this type of approach as an example of successful troubleshooting investigations. While corporate leaders maintain and grow plans for expansion, ZTE employees in all regions carry out with individual efforts towards internationalization of the company. Momentum continues to be built, in all levels, from office interns to veteran engineers, who work together to bring global focus into their daily work. If you would like to subscribe to this magazine (electronic version) or review additional articles and relevant technical materials concerning ZTE products, please visit the technical support website of ZTE CORPORATION (http://ensupport.zte.com.cn). If you have any ideas and suggestions or want to offer your contributions, you can contact us at any time via the following email: doc@zte.com.cn. Thank you for making ZTE a part of your telecom experience!
Contents
Brief Introduction About uRPF ............................................................................................................2
Active/Standby VRRP Switchover Failure on the ZXR10 6902 ..........................................................4
Base Station Offline Failure for a Loop in the Network of ZXR10 8902 ...............................................6
ZXR10 T8000 Router Reflector Fails to Reflect VPN Routing Information ..........................................8
FTP Service Failure for Incorrect MTU Setting in the MPLS Network .................................................10
Interconnection Failure between M6000 and Transmission Devices ..................................................12
Active/standby Load Sharing Failure on Multiple Uplinks of the ZXR10 T600 .....................................15
IPTV Users Fails to Watch Programs after the Multicast Service of M6000 is Activated ....................24
Charging Messages on the M6000 are Sent to Two Different Servers ...............................................27
Routing Forward Table Failure for Incorrect BGP Synchronization Setting .........................................28
FAQ .....................................................................................................................................................34
Technical Special
2 ︱Maintenance Experience Issue 276
Brief Introduction About uRPF
Yang Zhiwei / ZTE Corporation
1 uRPF Overview
Unicast Reverse Path Forwarding (uRPF)
prevents the network attacks resulting from
source address spoofing. The reverse path
forwarding is relative to the normal path
forwarding. After receiving packets, routers
obtain destination addresses of packets and
then find routes in accordance with the
destination addresses. If the corresponding
routes are found, packets will be forwarded. If
the corresponding routes are not found,
packets will be discarded.
By obtaining source addresses and
ingresses of packets, the uRPF function uses
source addresses as destination addresses,
and checks whether the interfaces
corresponding to the source addresses in the
forwarding table match ingresses. If the
interface matching fails, it is considered that
the source addresses are fake addresses. In
this case, packets are discarded. With this
method, the uRPF function can effectively
protect the network from malicious attacks
caused by source address modification.
2 uRPF Configuration
The following describes the uRPF
function limitations and configurations on ZTE
high-end switches, routers, and BRAS
products.
(1) Switch
High-end switches support the uRPF
function, but XG-line cards of G-series
switches do not support the uRPF function.
The configuration is as follows:
Enable the URPF function in physical
interface configuration mode:
ZXR10(config-if)#ip verify {strict |
loose}
It is recommended to use the strict mode
for all downstream interfaces, and the loose
mode for all upstream interfaces.
(2) T600/T1200 router
All T600/T1200 routers support the uRPF
function. The configuration is as follows:
Enable the URPF function in physical
interface configuration mode:
ZXR10(config)#interface
<interface-name>
ZXR10(config-if)#ip verify {strict |
loose}
It is recommended to use the strict mode
for all downstream interfaces, and the loose
mode for all upstream interfaces.
(3) M6000 router
The M6000 router supports the uRPF
function. The configuration is as follows:
Downstream interfaces:
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Data Products Special Issue Issue 1, 2013︱ 3
Method 1, configure the uRPF function
in global configuration mode:
ZXR10(config)#ipv4 verify unicast
source reachable-via rx interface
<interface-name>
Method 2, configure the uRPF function
in interface configuration mode:
ZXR10(config)#interface
<interface-name>
ZXR10(config-if)#ipv4 verify unicast
source reachable-via rx
Upstream interfaces:
Method 1, configure the uRPF function
in global configuration mode:
ZXR10(config)#ipv4 verify unicast
source reachable-via any interface
<interface-name>
Method 2, configure the uRPF function
in interface configuration mode:
ZXR10(config)#interface
<interface-name>
ZXR10(config-if)#ipv4 verify unicast
source reachable-via any
(4) BAS device
For users connected to VBUI interfaces
of T600, T1200, and M6000 routers, a user
table listing the relationship between the
users and IP addresses exists on the
Broadband Access Server (BAS). If a user IP
address does not match that in the user table
on the BAS, the BAS does not forward
packets. The VBUI interface of the BAS
supports the uRPF function by default.
3 uRPF FAQ
(1) Question: Is the uRPF function is
limited by hardware or software versions of
switches, routers, and BAS devices?
Answer: All hardware (except the XG-line
card of G-series switches) and the current
popular versions support the uRPF function.
(2) Question: Is the URPF function
configured for physical interfaces or
sub-interfaces? Do sub-interfaces inherit the
URPF function of real interfaces?
Answer: Physical interfaces are
independent from sub-interfaces, so both
physical interfaces and sub-interfaces should
be configured with the URPF function. Real
interfaces are independent from
sub-interfaces, so sub-interfaces do not
inherit the URPF function of real interfaces.
(3) Question: Whether to enable the
uRPF function on SmartGroup interfaces?
Answer: The URPF function is enabled
on SmartGroup interfaces of T600/T1200
/M6000.
Maintenance Instances
4 ︱Maintenance Experience Issue 276
Active/Standby VRRP Switchover
Failure on the ZXR10 6902
Zhang Jie / ZTE Corporation
Abstract: This section describes the active/standby VRRP switchover failure between two 6902 devices.
The analysis results show that this fault results from the incorrect VLAN setting for interfaces of the
heartbeat line.
Key words:6900, VRRP, active/standby switchover, VLAN, heartbeat line
1 Symptom
As shown in Figure 1, two 6902 devices
act as convergent devices. The upstream
interfaces of 6902 devices are connected to
T64E, while the downstream interfaces of
6902 devices are connected to two 2920
switches that are enabled with the VRRP
function. VRRP packets are transmitted
through the heartbeat line between 6902-1
and 6902-2.
Figure 1. 6902 VRRP Active/Standby
Network Diagram
In general, 6902-1 is in Master status,
and 6902-2 is in Backup status. If the link
between 6902-1 and the corresponding
downstream 2920 is broken, the VRRP
active/standby switchover between 6902-1
and 6902-2 fails. In this case, 6902-1 is still in
Master status, and 6902-2 is still in Backup
status.
2 Fault Analysis
(1) 6902-2 is still in Backup status. It is
judged that 6902-1 still sends VRRP packets
through the heartbeat line, and the data
stream of the heartbeat line is normal after the
downlink of 6902-1 is broken. To verify this
conclusion, the engineer breaks the heartbeat
line. The displayed result on 6902-2 is as
follows:
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Data Products Special Issue Issue 1, 2013︱ 5
6902-2(config)#
11:10:42 03/14/2009 UTC alarm 512 occurred %PORT% Interface down on gei_1/2 sent
by MEC 1
11:10:44 03/14/2009 UTC alarm 22016 occurred %VRRP% Group 1 of vlan10 changing to
Master sent by MEC 1
The displayed result shows that 6902-1 still sends VRRP packets when its downlink is
broken. All the above information shows that the fault results from 6902-1.
(2) If 6902-1 finds that the interface used by the VRRP group is down, it stops sending
VRRP packets, and then the VRRP active/standby switchover is performed. That is to say,
6902-1 does not find that the downlink is broken, or the downlink is still in UP status.
Check the configuration of used interfaces, such as vlan10, in VRRP Group 1,.
interface vlan 10
ip address 10.40.108.253 255.255.255.0
vrrp 1 priority 200
vrrp 1 out-interface gei_1/2
vrrp 1 ip 10.40.108.254
(3) Check the statuses of used interfaces, such as vlan10, in the VRRP group,.
6902-2(config)#show interface vlan10
vlan10 is up, line protocol is up
(4) VLAN10 is in UP status, so 6902-1 still sends VRRP packets. Only one 2920 switch is
connected to 6902-1, why VLAN10 is still in UP status?
6902-2(config)#show vlan id 10
VLAN Name Status Said MTU IfIndex PvidPorts UntagPorts TagPorts
------------------------------------------------------------------------
10 VLAN0010 active 100010 1500 0 gei_1/1-2
(5) The heartbeat egress is VLAN1. The heartbeat egress of 6902-2 belongs to another
VLAN and there is no loop, but this configuration interferes with the normal operation of 6902-1.
3 Solution
The problem is solved after interface gei_1/2 is deleted from VLAN10.
4 Conclusion
The VRRP active/standby switchover is triggered by the VLAN protocol status of interfaces
used by the VRRP group. After a heartbeat line is configured, you must ensure that the status of
the downlink should be consistent with the VLAN protocol status of the corresponding
interface.
Maintenance Instances
6 ︱Maintenance Experience Issue 276
Base Station Offline Failure for a
Loop in the Network of ZXR10 8902
Li Yong / ZTE Corporation
Abstract: This section describes the offline fault of base stations caused by a loop.
Key words: 8902, loop, base station offline, high-usage, SuperVLAN
1 Symptom
ZXR10 8902 switch in a network acts as
a gateway, and tens of 2G or 3G base
stations connected to the ZXR10 8902 switch
are often offline. After telneting to this switch,
engineers cannot execute any command
properly.
2 Fault Analysis
(1) Engineers telnet to 8902 remotely and
check device alarms. The OSPF connection
between this switch and that of a central office
interrupts frequently, and there is no rule.
(2) The CPU usage of the only NP line
card of this switch exceeds 80%, and the MP
usage of the master main control board is up
to 80%. The pre-judgment result is that there
is a loop in the network.
ZXR10#show logging alarm
alarm 16901 occurred %OAM% CPU load
exceeds the highest threshold 75% MP(M)
panel 1 current CPU load is: 98% sent by
MEC 1
(3) Engineers turn on the MAC address
floating switch of 8902. No MAC address
floating alarm is generated.
ZXR10(config)#mac logging-alarm
mac-move enable
(4) Engineers observe the traffic of
interfaces gei_2/19 and gei_2/20 connected to
this switch. There is no obvious abnormality,
and the increment of broadcast packets and
multicasts are smooth.
(5) When the out-of-band management
interface gei_2/20 of this switch that connects
to a L2 network device is disabled, engineers
still cannot execute any command properly in
Telnet mode, and the CPU usage of both the
line card and the main control board is high.
After that, engineers enable this interface.
(6) When the out-of-band management
interface gei_2/19 of this switch that connects
to a L2 network device is disabled, engineers
can execute all commands properly in Telnet
mode, the CPU usage of both the line card
and the main control board is normal. The
pre-judgment result is that many packets exist
in interface gei_2/19, so the CPU usage of
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Data Products Special Issue Issue 1, 2013︱ 7
both the line card and the main control board
is high.
(7) Engineers enable interface gei_2/19
and then obtain CPU packets of the above
line card by executing the capture command.
The command is as follows:
ZXR10(config)#capture npc 2
readspeed 10
(8) Engineers enable interface gei_2/19
and then obtain the following information:
ARP Packet on NPC: 2
OP SND_MAC SND_IP DST_MAC DST_IP DIR Port
1 0000.5e00.0101 10.127.76.129 0000.0000.0000 255.255.255.255 RX 19
1 0000.5e00.0101 10.127.76.129 0000.0000.0000 255.255.255.255 RX 19
1 0000.5e00.0101 10.127.76.129 0000.0000.0000 255.255.255.255 RX 19
1 0000.5e00.0101 10.127.76.129 0000.0000.0000 255.255.255.255 RX 19
1 0000.5e00.0101 10.127.76.129 0000.0000.0000 255.255.255.255 RX 19
1 0000.5e00.0101 10.127.76.129 0000.0000.0000 255.255.255.255 RX 19
ARP Packet on NPC: 2
OP SND_MAC SND_IP DST_MAC DST_IP DIR Port
1 0000.5e00.0101 10.127.76.129 0000.0000.0000 255.255.255.255 RX 19
1 0000.5e00.0101 10.127.76.129 0000.0000.0000 255.255.255.255 RX 19
1 0000.5e00.0101 10.127.76.129 0000.0000.0000 255.255.255.255 RX 19
1 0000.5e00.0101 10.127.76.129 0000.0000.0000 255.255.255.255 RX 19
1 0000.5e00.0101 10.127.76.129 0000.0000.0000 255.255.255.255 RX 19
1 0000.5e00.0101 10.127.76.129 0000.0000.0000 255.255.255.255 RX 19
1 0000.5e00.0101 10.127.76.129 0000.0000.0000 255.255.255.255 RX 19
1 0000.5e00.0101 10.127.76.129 0000.0000.0000 255.255.255.255 RX 19
1 0000.5e00.0101 10.127.76.129 0000.0000.0000 255.255.255.255 RX 19
1 0000.5e00.0101 10.127.76.129 0000.0000.0000 255.255.255.255 RX 19
1 0000.5e00.0101 10.127.76.129 0000.0000.0000 255.255.255.255 RX 19
IP Packet on NPC: 2
ProType DST_IP SRC_IP OVID IVID TTL PRO SRCPN DSTPN DIR Port
VRRP 224.0.0.18 10.127.76.129 1155 NULL 255 112 NULL NULL RX 19
VRRP 224.0.0.18 10.127.76.129 1154 NULL 255 112 NULL NULL RX 19
VRRP 224.0.0.18 10.127.76.129 1153 NULL 255 112 NULL NULL RX 19
VRRP 224.0.0.18 10.127.76.129 1152 NULL 255 112 NULL NULL RX 19
VRRP 224.0.0.18 10.127.76.129 1151 NULL 255 112 NULL NULL RX 19
VRRP 224.0.0.18 10.127.76.129 1150 NULL 255 112 NULL NULL RX 19
VRRP 224.0.0.18 10.127.76.129 1149 NULL 255 112 NULL NULL RX 19
VRRP 224.0.0.18 10.127.76.129 1148 NULL 255 112 NULL NULL RX 19
VRRP 224.0.0.18 10.127.76.129 1147 NULL 255 112 NULL NULL RX 19
VRRP 224.0.0.18 10.127.76.129 1146 NULL 255 112 NULL NULL RX 19
VRRP 224.0.0.18 10.127.76.129 1145 NULL 255 112 NULL NULL RX 19
VRRP 224.0.0.18 10.127.76.129 1144 NULL 255 112 NULL NULL RX 19
Maintenance Instances
8 ︱Maintenance Experience Issue 276
(9) The printed information shows that
interface gei_2/19 receives many ARP
packets and VRRP protocol packets. The
configuration shows that all source addresses
of these packets are configured on a
SuperVLAN interface of 8902, and interface
SuperVLAN is enabled with the VRRP
function. The printed OVID information is
consistent with the SubVLAN information of
the SuperVLAN interface. The SuperVLAN
interface is the gateway for interface gei_2/19
connected with these offline base stations.
The above result shows that the network
where interface gei_2/19 is connected to has
a loop. Packets sent from interface gei_2/19
by 8902 are also sent to interface gei_2/19, so
the CPU usage of the line card is high. This
OSPF connection is broken, so the base
stations are often offline.
3 Solution
The above analysis shows that there is a
loop in the network. After going to the field,
related engineers find that the loop is caused
by the network cabling failure during the
commissioning. The fault is solved after the
loop is deleted.
ZXR10 T8000 Router Reflector Fails to Reflect VPN Routing Information
Fan Wei / ZTE Corporation
Abstract: This section describes if T8000 that acts as a router reflector needs to reflect VPN routing
information, the Route-Target attribute filtering function must be disabled.
Key words: T8000, vpnv4, reflector, VRF, MPLS, Route-Target
1 Symptom
As shown in Figure 1, T8000 acting as a
router reflector is connected to two M6000
devices, and runs L3 MPLS VPN services.
After the Label Distribution Protocol (LDP)
and VPNv4 are configured, the neighbour
relationship of two M6000 devices is
established successfully, but these two
M6000 devices cannot learn routes from each
other.
Figure 1. T8000 Router Reflector Topology
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Data Products Special Issue Issue 1, 2013︱ 9
2 Fault Analysis
The possible reasons are as follows:
(1) VPN route information is not notified.
(2) The RT setting of two M6000 devices
is incorrect.
(3) T8000 does not forward VPN routes.
(4) VPN routes are filtered.
Perform the following steps to locate the
fault:
(1) Check the Label Distribution Protocol
(LDP) forwarding table. The related labels are
allocated properly.
(2) After establishing the corresponding
VRF on T8000, engineers find that M6000
devices can learn VRF routes from each other.
Once when the VRF is deleted, VRF routes
disappear.
(3) The BGP protocol supports the
MPLS-VPN application. For VPNv4 routes,
the Route-Target attribute must be enabled.
For router reflectors and inter-domain EBGPs,
the Route-Target function must be disabled. If
not, router reflectors will filter VRF RTs. In this
case, the client cannot receive related
information, so VRF routes of the peer end
cannot be learnt.
3 Solution
After the no bgp default route-target filter
command is executed in the BGP
configuration of T8000, two M6000 devices
can learn VPN routes from each other. The
fault is solved.
4 Conclusion
During the router reflector configuration,
the Route-Target attribute filtering function is
enabled by default. To reflect related VPN
route information, you need to execute the no
bgp default route-target filter command to
disable the Route-Target function.
Maintenance Instances
10 ︱Maintenance Experience Issue 276
FTP Service Failure for Incorrect MTU Setting in the MPLS Network
Li Jing / ZTE Corporation
Abstract: The Maximum Transfer Unit (MTU) of an interface on a router is smaller than the length of
a packet, so the FTP client cannot transfer files to the FTP server. This fault is solved after the MTU of an
interface on the router is modified.
Key words: MPLS, FTP, MTU, fragment
1 Symptom
Most bearer networks use the MPLS
network. In core networks, files, such as LOG
files, are transferred between the FTP client
and the FTP server through the MPLS
network, as shown in Figure 1.
Normally, the FTP client can successfully
ping the IP address of the FTP server.
However, files cannot be transferred even if
the FTP client can successfully ping the FTP
server.
2 Fault Analysis
(1) Engineers can successfully ping the
FTP server from the FTP client, which means
that the VPN route is normal.
(2) Files cannot be transferred when the
FTP client can successfully ping the FTP
server, which means that maybe the MTU
setting is incorrect.
Figure 1. FTP Service Failure for Incorrect MTU Setting in the MPLS Network
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Data Products Special Issue Issue 1, 2013︱ 11
In general, the MTU for an interface of a
network device, including the clients and the
server in the core network, is set to 1500
bytes by default. When a packet passes
through an MPLS network, two layers of TAG
labels are added. The length of each TAG
label is 4 bytes. In this case, the total bytes of
a packet with 1500 bytes on the PE side
become 1508 bytes, which exceeds the MTU
that is set for an interface on the router. In this
case, the packet is discarded.
3 Solution
After setting the IP MTU for interfaces on
the network side of routers in the network to
1508 bytes, the FTP service becomes normal.
If there is a transmission device between
routers, and the IP MTU cannot be modified
by the transmission device. You need to set
the IP MTU of interfaces on routers to the
default value (1500 bytes), and then set the IP
MTU of the system to 1492 bytes on both the
FTP client and the FTP server. In this case,
the FTP service also becomes normal.
4 Conclusion
The FTP service does not fragment a
packet during the transmission. When a
packet passes through an MPLS network, the
packet will be discarded if the size of the
packet exceeds the set IP MTU.
When the service is invalid after the
device route in a network is connected, you
need to consider the setting of the IP MTU.
Maintenance Instances
12 ︱Maintenance Experience Issue 276
Interconnection Failure between M6000 and Transmission Devices
Li Yunfeng / ZTE Corporation
Abstract: This section describes the interconnection failure between M6000 and transmission devices.
The analysis results show that the fault results from inconsistent V5 bytes. This fault is solved after the V5
byte is modified.
Key words: M6000, CPOS, E1, transmission, interconnection
1 Symptom
During the network reconstruction of one
company, M6000 interconnects with
transmission devices of other manufacturers
and E1 links of each sub-company through
the CPOS. However, the E1 link divided by
the CPOS cannot interconnect with the E1 link
of a sub-company successfully.
Figure 1. Interconnection Between M6000 and Transmission Device through the CPOS
2 Fault Analysis
(1) The network and router (including the
version) of this company are the same as
those of the associated companies. The E1
interconnection in other networks is
successful, so the fault is unrelated to the
router and its version.
(2) The intermediate transmission
devices are from the same manufacturer. The
only difference is that the transmission device
of this company is updated. Maybe the
interconnection fault may result from the
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Data Products Special Issue Issue 1, 2013︱ 13
parameter change after the update of the
transmission device.
(3) When executing the show controller
cpos3-0/0/0/1 command on M6000, engineers
find that the E1 interconnection of the CPOS
high order path (AU4) is normal, but that of
the lower order path (VC12) is unsuccessful.
The detailed information are as follows:
M6000#show controller e1 cpos3-0/0/0/1 au4 1 tug3 2 tug2 2 e1 1
Low order path: AU-4 1, TUG-3 2, TUG-2 2, C-12 1
Active Alarm: TIM
History Alarm: AIS = 2 RDI = 2
LOP = 0 LOM = 2
TIM = 2 TIU = 2
SLM = 0 SLU = 0
PDI = 0 UNEQP = 0
Error : BIP2 = 0 LPREI(V5) = 16284
NEWPTR = 0 PSE = 0
NSE = 0
V5(TX): 0x01
V5(RX): 0x02
V5(EX): 0x01
J2(TX): "ZTE ZXR10 T8000"
CRC-7 : 0xaf
5a 54 45 20 5a 58 52 31 30 20 54 38 30 30 30
J2(RX): "HuaWei SBS "
CRC-7 : 0x96
48 75 61 57 65 69 20 53 42 53 20 20 20 20 20
J2(EX): "ZTE ZXR10 T8000"
CRC-7 : 0xaf
5a 54 45 20 5a 58 52 31 30 20 54 38 30 30 30
E1 is down
Work mode: unframed
Clock source: internal
Loopback: not set
Active Alarm: NONE
History Alarm: LOS = 0 AIS = 0
LOF = 0 RAI = 0
AISD = 0 CRCMLOF = 0
CRCMCRC = 0 CRCMCFEBE = 0
CRCMOOF = 0 CASMLOF = 0
CASMRMAI = 0 CASMAISD = 0
Error : FER = 0 CRCERR = 0
FEBE = 0
Maintenance Instances
14 ︱Maintenance Experience Issue 276
The above information shows that there
are many lower-order path remote error
indication (LPREI) errors on M6000. This
alarm results from the inconsistency of V5
bytes of both devices. The above information
shows that the V5 byte sent by the router is
0x01, but the V5 byte received from the peer
end is 0x02. This is the reason why E1
interconnection fails.
3 Solution
Solution 1, Set the V5 byte of the
transmission device to 0x01 in order to be
consistent with that of M6000.
Solution 2, Set the V5 byte of M6000 to
0x02 in order to be consistent with that of the
transmission device.
The modification commands on M6000
are as follows (010 in binary format is equal to
0x02 in Hex format):
controller cpos3-0/0/0/1
framing sdh
aug mapping au4
au4 1 tug3 1
mode e1
tug2 1 e1 1
flag v5 010
4 Conclusion
During the interconnection of
transmission devices from different
manufacturers, the parameter configuration
must be consistent.
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Data Products Special Issue Issue 1, 2013︱ 15
Active/standby Load Sharing Failure on Multiple Uplinks of the ZXR10 T600
Wang Lei / ZTE Corporation
Abstract: The cost value calculated by the OSPF is the same, so the traffic passes through each uplink.
In this case, the link with a wide bandwidth cannot be the master link, and the link with a narrow
bandwidth cannot be a standby link. This fault is solved after the reference bandwidth that is used by the
OSPF during calculating the cost value is modified.
Key words: T600, OSPF, cost, reference bandwidth, active/standby link
1 Symptom
As shown in Figure 1, the ZXR10 T600
BRAS of one area has six 1GE uplinks (black
line). Two 10GE boards are added, that is to
say, two 10G uplinks are added (red line). In
this case, there are eight uplinks. It is hoped
that the traffic is forwarded through two 10GE
uplinks, and six 1GE uplinks are backup links.
After the service cutover, the traffic
passes through eight uplinks instead of the
two 10GE uplinks.
2 Fault Analysis
(1) Check the configuration of
T600-BRAS. The OSPF configuration is as
follows:
Figure 1. Topology of T600 with Multiple Uplinks
router ospf 100
router-id 10.20.252.77
maximum-paths 8 /* eight uplinks share the load*/
network 10.10.129.54 0.0.0.0 area 0.0.1.10
network 10.10.129.58 0.0.0.0 area 0.0.1.10
network 10.10.231.19 0.0.0.0 area 0.0.1.10
network 10.10.241.34 0.0.0.0 area 0.0.1.10
network 10.10.241.38 0.0.0.0 area 0.0.1.10
Maintenance Instances
16 ︱Maintenance Experience Issue 276
network 10.10.241.54 0.0.0.0 area 0.0.1.10
network 10.10.241.58 0.0.0.0 area 0.0.1.10
network 10.20.244.182 0.0.0.0 area 0.0.1.10
network 10.20.244.186 0.0.0.0 area 0.0.1.10
network 10.20.244.190 0.0.0.0 area 0.0.1.10
network 10.20.252.77 0.0.0.0 area 0.0.1.10
(2) When checking the cost value of the OSPF interface by executing the show ip ospf
interface command, engineers find that the cost value of both 1GE ports and expanded 10GE
ports is 1.
ZXR10#show ip ospf interface
OSPF Router with ID (10.20.252.77) (Process ID 100)
xgei_3/1 is up
Internet Address 10.10.129.54 255.255.255.252 enable
Up for 8w0d
In the area 0.0.1.10 POINT_TO_POINT
Cost 1, Priority 1, Network Type point-to-point
Transmit Delay(sec) 1, Authentication Type null
Timer intervals(sec) : Hello 10, Dead 40, Retransmit 5
Number of Neighbors 1, Number of Adjacent neighbors 1
10.10.255.230
xgei_5/1 is up
Internet Address 10.10.129.58 255.255.255.252 enable
Up for 8w0d
In the area 0.0.1.10 POINT_TO_POINT
Cost 1, Priority 1, Network Type point-to-point
Transmit Delay(sec) 1, Authentication Type null
Timer intervals(sec) : Hello 10, Dead 40, Retransmit 5
Number of Neighbors 1, Number of Adjacent neighbors 1
10.10.255.231
gei_2/5 is up
Internet Address 10.10.241.34 255.255.255.252 enable
Up for 36w1d
In the area 0.0.1.10 POINT_TO_POINT
Cost 1, Priority 1, Network Type point-to-point
Transmit Delay(sec) 1, Authentication Type null
Timer intervals(sec) : Hello 10, Dead 40, Retransmit 5
Number of Neighbors 1, Number of Adjacent neighbors 1
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Data Products Special Issue Issue 1, 2013︱ 17
10.10.255.231
gei_6/1 is up
Internet Address 10.10.241.38 255.255.255.252 enable
Up for 8w0d
In the area 0.0.1.10 POINT_TO_POINT
Cost 1, Priority 1, Network Type point-to-point
Transmit Delay(sec) 1, Authentication Type null
Timer intervals(sec) : Hello 10, Dead 40, Retransmit 5
Number of Neighbors 1, Number of Adjacent neighbors 1
10.10.255.230
gei_1/5 is up
Internet Address 10.10.241.54 255.255.255.252 enable
Up for 8w0d
In the area 0.0.1.10 POINT_TO_POINT
Cost 1, Priority 1, Network Type point-to-point
Transmit Delay(sec) 1, Authentication Type null
Timer intervals(sec) : Hello 10, Dead 40, Retransmit 5
Number of Neighbors 1, Number of Adjacent neighbors 1
10.10.255.230
gei_8/1 is up
Internet Address 10.10.241.58 255.255.255.252 enable
Up for 14w2d
In the area 0.0.1.10 POINT_TO_POINT
Cost 1, Priority 1, Network Type point-to-point
Transmit Delay(sec) 1, Authentication Type null
Timer intervals(sec) : Hello 10, Dead 40, Retransmit 5
Number of Neighbors 1, Number of Adjacent neighbors 1
10.10.255.231
gei_1/1 is up
Internet Address 10.20.244.182 255.255.255.252 enable
Up for 8w0d
In the area 0.0.1.10 POINT_TO_POINT
Cost 1, Priority 1, Network Type point-to-point
Transmit Delay(sec) 1, Authentication Type null
Timer intervals(sec) : Hello 10, Dead 40, Retransmit 5
Number of Neighbors 1, Number of Adjacent neighbors 1
10.10.255.231
gei_2/1 is up
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18 ︱Maintenance Experience Issue 276
Internet Address 10.20.244.186 255.255.255.252 enable
Up for 8w0d
In the area 0.0.1.10 POINT_TO_POINT
Cost 1, Priority 1, Network Type point-to-point
Transmit Delay(sec) 1, Authentication Type null
Timer intervals(sec) : Hello 10, Dead 40, Retransmit 5
Number of Neighbors 1, Number of Adjacent neighbors 1
10.10.255.230
(3) The cost value is calculated by the
automatic calculation formula in the OSPF
protocol, that is to say, the ospf cost value
(round down) of an interface is equal to
100/interface bandwidth. For the gei interface,
the cost value is the round-off number of 0.1,
that is to say, the cost value is 1. For the
10GE interface, the cost value is also the
round-off number of 0.01, that is to say, the
cost value is also 1. In this case, the cost
value of interface gei and interface xgei is the
same, so the initial requirement cannot be
met.
3 Solution
You can execute the auto-cost
reference-bandwidth <1-4000000> command
to modify the reference bandwidth in the
OSPF configuration and then modify the cost
value. The configuration after the modification
is as follows:
router ospf 100
router-id 10.20.252.77
auto-cost reference-bandwidth 10000 /*adding a reference bandwidth*/
maximum-paths 8 /* eight links share the load*/
network 10.10.129.54 0.0.0.0 area 0.0.1.10
network 10.10.129.58 0.0.0.0 area 0.0.1.10
network 10.10.231.19 0.0.0.0 area 0.0.1.10
network 10.10.241.34 0.0.0.0 area 0.0.1.10
network 10.10.241.38 0.0.0.0 area 0.0.1.10
network 10.10.241.54 0.0.0.0 area 0.0.1.10
network 10.10.241.58 0.0.0.0 area 0.0.1.10
network 10.20.244.182 0.0.0.0 area 0.0.1.10
network 10.20.244.186 0.0.0.0 area 0.0.1.10
network 10.20.244.190 0.0.0.0 area 0.0.1.10
network 10.20.252.77 0.0.0.0 area 0.0.1.10
Execute the show ip ospf interface command to check the port after the modification. The
result is as follows:
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Data Products Special Issue Issue 1, 2013︱ 19
ZXR10#show ip ospf interface
OSPF Router with ID (10.20.252.77) (Process ID 100)
xgei_3/1 is up
Internet Address 10.10.129.54 255.255.255.252 enable
Up for 8w0d
In the area 0.0.1.10 POINT_TO_POINT
Cost 1, Priority 1, Network Type point-to-point
Transmit Delay(sec) 1, Authentication Type null
Timer intervals(sec) : Hello 10, Dead 40, Retransmit 5
Number of Neighbors 1, Number of Adjacent neighbors 1
10.10.255.230
xgei_5/1 is up
Internet Address 10.10.129.58 255.255.255.252 enable
Up for 8w0d
In the area 0.0.1.10 POINT_TO_POINT
Cost 1, Priority 1, Network Type point-to-point
Transmit Delay(sec) 1, Authentication Type null
Timer intervals(sec) : Hello 10, Dead 40, Retransmit 5
Number of Neighbors 1, Number of Adjacent neighbors 1
10.10.255.231
gei_2/5 is up
Internet Address 10.10.241.34 255.255.255.252 enable
Up for 36w1d
In the area 0.0.1.10 POINT_TO_POINT
Cost 10, Priority 1, Network Type point-to-point
Transmit Delay(sec) 1, Authentication Type null
Timer intervals(sec) : Hello 10, Dead 40, Retransmit 5
Number of Neighbors 1, Number of Adjacent neighbors 1
10.10.255.231
gei_6/1 is up
Internet Address 10.10.241.38 255.255.255.252 enable
Up for 8w0d
In the area 0.0.1.10 POINT_TO_POINT
Cost 10, Priority 1, Network Type point-to-point
Transmit Delay(sec) 1, Authentication Type null
Timer intervals(sec) : Hello 10, Dead 40, Retransmit 5
Number of Neighbors 1, Number of Adjacent neighbors 1
10.10.255.230
Maintenance Instances
20 ︱Maintenance Experience Issue 276
gei_1/5 is up
Internet Address 10.10.241.54 255.255.255.252 enable
Up for 8w0d
In the area 0.0.1.10 POINT_TO_POINT
Cost 10, Priority 1, Network Type point-to-point
Transmit Delay(sec) 1, Authentication Type null
Timer intervals(sec) : Hello 10, Dead 40, Retransmit 5
Number of Neighbors 1, Number of Adjacent neighbors 1
10.10.255.230
gei_8/1 is up
Internet Address 10.10.241.58 255.255.255.252 enable
Up for 14w2d
In the area 0.0.1.10 POINT_TO_POINT
Cost 10, Priority 1, Network Type point-to-point
Transmit Delay(sec) 1, Authentication Type null
Timer intervals(sec) : Hello 10, Dead 40, Retransmit 5
Number of Neighbors 1, Number of Adjacent neighbors 1
10.10.255.231
gei_1/1 is up
Internet Address 10.20.244.182 255.255.255.252 enable
Up for 8w0d
In the area 0.0.1.10 POINT_TO_POINT
Cost 10, Priority 1, Network Type point-to-point
Transmit Delay(sec) 1, Authentication Type null
Timer intervals(sec) : Hello 10, Dead 40, Retransmit 5
Number of Neighbors 1, Number of Adjacent neighbors 1
10.10.255.231
gei_2/1 is up
Internet Address 10.20.244.186 255.255.255.252 enable
Up for 8w0d
In the area 0.0.1.10 POINT_TO_POINT
Cost 10, Priority 1, Network Type point-to-point
Transmit Delay(sec) 1, Authentication Type null
Timer intervals(sec) : Hello 10, Dead 40, Retransmit 5
Number of Neighbors 1, Number of Adjacent neighbors 1
10.10.255.230
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Data Products Special Issue Issue 1, 2013︱ 21
Check the port traffic. The detailed information is as follows:
ZXR10#show interface xgei_3/1
xgei_3/1 is up, line protocol is up
MAC address is 00d0.d0c0.0320
The port is optical
Duplex full
ARP Timeout: 04:00:00
Internet address is 10.10.129.54/30
IP MTU 1500 bytes
MRU 7600 bytes
MTU 1600 bytes BW 10000000 Kbits
Last clearing of "show interface" counters never
120 seconds input rate : 616702041Bps, 710654 pps
120 seconds output rate: 196551666Bps, 461783 pps
Interface peak rate :
input 725773412Bps,output 281997203Bps
Interface utilization : input 49%, output 15%
Input:
Packets : 6237211371020 Bytes : 5040435755736334
Unicasts : 6237203196739 Multicasts: 7880991
Broadcasts: 293290 64B : 333351442209
65-127B : 1706566208851 128-255B : 314313153568
256-511B : 118028738416 512-1023B : 144522828338
1024-1518B: 3620266192982 Undersize : 0
Oversize : 162806656 CRC-ERROR : 0
Output:
Packets : 4873272205284 Bytes : 2197434703453395
Unicasts : 4873265252433 Multicasts: 6952748
Broadcasts: 103 64B : 869560676016
65-127B : 1995645961955 128-255B : 295637721093
256-511B : 64218865493 512-1023B : 93262949507
1024-1518B: 1554051505129 Oversize : 894526091
ZXR10#show interface xgei_5/1
xgei_5/1 is up, line protocol is up
MAC address is 00d0.d0c0.0320
The port is optical
Duplex full
ARP Timeout: 04:00:00
Internet address is 10.10.129.58/30
IP MTU 1500 bytes
MRU 7600 bytes
MTU 1600 bytes BW 10000000 Kbits
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22 ︱Maintenance Experience Issue 276
Last clearing of "show interface" counters never
120 seconds input rate : 403812482Bps, 485311 pps
120 seconds output rate: 218689720Bps, 513997 pps
Interface peak rate :
input 699525271Bps,output 294246049Bps
Interface utilization : input 32%, output 17%
Input:
Packets : 5909167868576 Bytes : 4765843744345818
Unicasts : 5909159861800 Multicasts: 7712909
Broadcasts: 293867 64B : 311979849260
65-127B : 1626534764575 128-255B : 297439240589
256-511B : 111511295278 512-1023B : 136637845848
1024-1518B: 3424957650589 Undersize : 0
Oversize : 107224174 CRC-ERROR : 1737
Output:
Packets : 5455649213711 Bytes : 2460199055761584
Unicasts : 5455642263119 Multicasts: 6950474
Broadcasts: 118 64B : 982469129919
65-127B : 2222358893314 128-255B : 332457557334
256-511B : 73619528091 512-1023B : 106630120260
1024-1518B: 1735509368992 Oversize : 2604615801
ZXR10#show interface gei_1/1 /* Other GE ports are just similar*/
gei_1/1 is up, line protocol is up
MAC address is 00d0.d0c0.0320
The port is optical
Duplex full
ARP Timeout: 04:00:00
Internet address is 125.45.244.182/30
IP MTU 1500 bytes
MRU 7600 bytes
MTU 1600 bytes BW 1000000 Kbits
Last clearing of "show interface" counters never
120 seconds input rate : 530Bps, 1 pps
120 seconds output rate: 533Bps, 1 pps
Interface peak rate :
input 122247269Bps,output 63363842Bps
Interface utilization : input 0%, output 0%
Input:
Packets : 1519036653750 Bytes : 1155108969461211
Unicasts : 1519020438964 Multicasts: 15689719
Broadcasts: 525067 64B : 85063231893
65-127B : 451390192631 128-255B : 83821966538
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Data Products Special Issue Issue 1, 2013︱ 23
256-511B : 26785522283 512-1023B : 41692690477
1024-1518B: 830237297111 Undersize : 0
Oversize : 45753245 CRC-ERROR : 417
Output:
Packets : 1208948795938 Bytes : 534669095751132
Unicasts : 1208932979755 Multicasts: 15816049
Broadcasts: 134 64B : 186289980847
65-127B : 526768727390 128-255B : 76365658974
256-511B : 13593552803 512-1023B : 25813774860
1024-1518B: 380074304673 Oversize : 42796391
The above information shows that the traffic passes through two 10GE ports, and there is no
traffic pass through the 1GE ports. The initial requirement is met.
4 Conclusion
You need to master the application of the auto-cost reference-bandwidth command in the
OSPF. You can execute this command to modify the reference bandwidth used by the OSPF
during calculating the cost value as required.
Maintenance Instances
24 ︱Maintenance Experience Issue 276
IPTV Users Fails to Watch Programs after the Multicast Service of M6000 is Activated
Yun Yuejun / ZTE Corporation
Abstract: This section describes that IPTV users cannot watch programs because the M6000
configuration is inconsistent with the T600 configuration.
Key words: M6000, T600, IPTV, multicast, static
1 Symptom
IPTV services of one area are activated,
and multicast duplication spots are set on
BRAS nodes. 50 pilot programs are activated
in advance. M6000 acts as the BRAS device,
and connects to convergence switches.
Convergence switches provide the access
function to the Optical Line Terminal (OLT),
Access Gateway (AG), and L2.
M6000 acts as the BRAS device when it
connects to the network for the first time, and
the IPTV service is activated. New IPTV users
can only watch programs on demand instead
of live programs. Engineers configure the
M6000 in accordance with theT600
configuration. But, IPTV pilot programs are
activated in the T600 configuration.
In accordance with the activation
requirements of users, static multicast groups
of 50 pilot programs activated in advance are
configured on the BRAS device. Static
multicast groups have the following
advantages:
(1) The multicast route is steady, and it
exists no matter multicast data exists or not.
(2) The management on the multicast
source and the multicast range is simple
because the multicast route is steady.
(3) No dynamic multicast route is
established, so the delay is low during the first
live program.
The IPTV service allocates two accounts
to users. One is the PPPoE account, which is
used to obtain IP address, and the other is the
IPTV platform account, which is used for the
IPTV platform authentication. After two
accounts are configured for the set-top box on
the user side, the set-top box can be
connected to the IPTV platform.
2 Fault Analysis
(1) M6000 and metropolitan area
networks (MANs) converge on the NE5000E
side, and the PIMSM neighbour is normal.
The mroute command shows that there are
(*,G) and (S,G) items and multiple channels.
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Data Products Special Issue Issue 1, 2013︱ 25
M6000#show ip pimsm neighbor
Neighbor Address Interface DR Priority Uptime Expires Ver
121.30.9.197 xgei-0/1/0/1 1 18d10h 00:01:33 V2
121.30.9.193 xgei-0/0/0/1 1 41d0h 00:01:25 V2
M6000#show ip mroute
(*, 226.0.2.41), RP: 218.26.134.127, TYPE: DYNAMIC, FLAGS: NS
Incoming interface: xgei-0/1/0/1, flags: NS
Outgoing interface list:
vbui2, flags: F/S
(10.112.2.69, 226.0.2.41), TYPE: DYNAMIC, FLAGS:
Incoming interface: xgei-0/1/0/1, flags:
Outgoing interface list:
vbui2, flags: F/S
(*, 226.0.2.42), RP: 218.26.134.127, TYPE: DYNAMIC, FLAGS: NS
Incoming interface: xgei-0/1/0/1, flags: NS
Outgoing interface list:
vbui2, flags: F/S
(10.112.2.69, 226.0.2.42), TYPE: DYNAMIC, FLAGS:
Incoming interface: xgei-0/1/0/1, flags:
Outgoing interface list:
vbui2, flags: F/S
(*, 226.0.2.43), RP: 218.26.134.127, TYPE: DYNAMIC, FLAGS: NS
Incoming interface: xgei-0/0/0/1, flags: NS
Outgoing interface list:
vbui2, flags: F/S
(10.112.2.68, 226.0.2.43), TYPE: DYNAMIC, FLAGS:
Incoming interface: xgei-0/0/0/1, flags:
Outgoing interface list:
vbui2, flags: F/S
(*, 226.0.2.44), RP: 218.26.134.127, TYPE: DYNAMIC, FLAGS: NS
Incoming interface: xgei-0/0/0/1, flags: NS
Outgoing interface list:
vbui2, flags: F/S
(10.112.2.68, 226.0.2.44), TYPE: DYNAMIC, FLAGS:
Incoming interface: xgei-0/0/0/1, flags:
Outgoing interface list:
vbui2, flags: F/S
(2) When checking the dialing information
of the top-set box, the user finds that the
bandwidth authentication is successful. When
the top-set box is connected to the IPTV
platform, the system prompts that the top-set
Maintenance Instances
26 ︱Maintenance Experience Issue 276
box cannot be connected to the remote
server.
(3) The above information about M6000
shows that the bandwidth account of the user
is online.
(4) In general, the generated (*,G) and
(S,G) items mean that multicast stream is sent
properly. The IPTV service of all users
connecting to the T600 device is normal.
(5) The M6000 router is first used for
China Unicom MAN, and engineers configure
the IPTV service of T6000 in accordance with
the T600 configuration. Engineers doubt that
maybe the configuration mode of different
software platforms is different. After
consultation, engineers find that the
configuration location of the static multicast
group on M6000 is incorrect.
The static multicast group on T600 is
configured on the VBUI interface.
interface vbui3
ip address 10.143.206.1
255.255.254.0
ip pim sm
ip igmp static-group 226.0.2.1
ip igmp static-group 226.0.2.2
ip igmp static-group 226.0.2.3
ip igmp static-group 226.0.2.4
The static multicast group on M6000 is
configured on the interface of the user side,
so users cannot watch IPTV programs.
subscriber-manage
igmp service-profile 1
static-group 226.0.2.1
static-group 226.0.2.2
static-group 226.0.2.3
static-group 226.0.2.4
3 Solution
It is not required to configure the static
group joint function for the multicast on the
user side. Static users are added to a group
when they are online. A user can be added to
multiple groups. In this case, heavy traffic will
be sent to the user, so the packet will be
discarded.
To split static stream, execute the
following commands:
M6000#(config)#ip multicast-routing
M6000#(config-mcast)#router igmp
M6000#(config-mcast-igmp)#interface
loopback1
M6000#(config-mcast-igmp-if-loopback
1)#static-group 226.0.2.1
M6000#(config-mcast-igmp-if-loopback
1)#static-group 226.0.2.2
M6000#(config-mcast-igmp-if-loopback
1)#static-group 226.0.2.3
M6000#(config-mcast-igmp-if-loopback
1)#static-group 226.0.2.4
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Data Products Special Issue Issue 1, 2013︱ 27
Charging Messages on the M6000 are Sent to Two Different Servers
Lv Zhongwei / ZTE Corporation
Abstract: This section describes charging messages on M6000 are sent to two different servers.
Key words: M6000, charging, RADIUS, copy to, domain name
1 Network Requirement
The IP addresses of the current RADIUS servers in a network are 10.10.97.5 and 10.10.97.3.
A new enabled service needs to copy the charging information in the abc.cn domain to
10.10.107.19.
2 Implementation Method
Configure the ZXR10 M6000:
/*Configure the source RADIUS group*/
radius authentication-group 1
server 1 10.10.97.5 master key 88----89 port 1645
server 2 10.10.97.3 key 88----89 port 1645
alias zradius
deadtime 1
nas-ip-address 222.83.19.8
/*Configure a RADIUS copying group on the BRAS*/
radius
accounting-group 100
server 1 10.10.107.19 key test port 1813
aaa-accounting-template 2
description Acct_zradius
aaa-accounting-type radius
accounting-radius-group first 1 second 100
/*Copy the charging information in the abc.cn domain to 10.10.107.19*/
accounting-template 2
description pppoe
bind aaa-accounting-template 2
domain 1
bind accounting-template 2
alias abc.cn
Maintenance Instances
28 ︱Maintenance Experience Issue 276
Routing Forward Table Failure for Incorrect BGP Synchronization Setting
Xu Xiaoguang / ZTE Corporation
Abstract: This section describes that routes fail to be forwarded because the BGP synchronization
function is not disabled.
Key words: BGP, synchronization, EBGP, IBGP, IGP
1 Symptom
As shown in Figure 1, the routing forwarding table of one router is abnormal.
Figure 1. DHCP Users Fail to Go Online
2 Fault Analysis
The results show that BGP synchroni-
zation function in the current network is not
disabled, so routing forward tables fail to be
generated. The following analyzes the
operations in cast that the BGP synchroni-
zation function is enabled or disabled:
(1) Command explanation: The no
synchronization command means that the
BGP synchronization function is disabled.
When the BGP synchronization function is
disabled, the BGP router notifies network
routes instead of waiting for the IGP
synchronization.
(2) Instructor explanation: When the BGP
synchronization function is enabled, the BGP
router cannot notify the BGP routes learnt
from the IBGP neighbor to its own EBGP
neighbor. The BGP router notifies the BGP
routes to the EBGP router except that these
BGP routes exist in the IGP routing table.
3 Solution
Configure the BGP on R3:
R3#show running-config bgp
! <BGP>
router bgp 200
redistribute connected
neighbor 2.2.2.2 remote-as 200
neighbor 2.2.2.2 activate
neighbor 2.2.2.2 next-hop-self
neighbor 2.2.2.2 update-source
loopback1
! </BGP>
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Data Products Special Issue Issue 1, 2013︱ 29
Check the local BGP routing table:
R3(config)#show ip bgp route
Status codes: *-valid, >-best, i-internal, s-stale
Origin codes: i-IGP, e-EGP, ?-incomplete
Dest NextHop Metric LocPrf RtPrf Path
*i 1.1.1.1/32 2.2.2.2 100 200 100 i
*> 3.3.3.3/32 3.3.3.3 0 0 ?
*> 100.1.1.4/30 100.1.1.6 0 0 ?
*i 172.16.0.0/24 2.2.2.2 100 200 100 i
*i 172.16.1.0/24 2.2.2.2 100 200 100 i
*i 172.16.2.0/24 2.2.2.2 100 200 100 i
*i 172.16.3.0/24 2.2.2.2 100 200 100 i
Check the local routing forward table:
R3#show ip forwarding route
IPv4 Routing Table:
status codes: *valid, >best
Dest Gw Interface Owner Pri Metric
*> 2.2.2.2/32 100.1.1.5 gei-0/0/0/2 ospf 110 1
*> 3.3.3.3/32 3.3.3.3 loopback1 address 0 0
*> 100.1.1.0/30 100.1.1.5 gei-0/0/0/2 ospf 110 2
*> 100.1.1.4/30 100.1.1.6 gei-0/0/0/2 direct 0 0
*> 100.1.1.6/32 100.1.1.6 gei-0/0/0/2 address 0 0
Change the configuration to no synchronization:
R3(config)#show running-config bgp
! <BGP>
router bgp 200
no synchronization
redistribute connected
neighbor 2.2.2.2 remote-as 200
neighbor 2.2.2.2 activate
neighbor 2.2.2.2 next-hop-self
neighbor 2.2.2.2 update-source loopback1
! </BGP>
The BGP routing table is added to the routing forward table.
R3#show ip forwarding route
IPv4 Routing Table:
status codes: *valid, >best
Dest Gw Interface Owner Pri Metric
*> 1.1.1.1/32 100.1.1.5 gei-0/0/0/2 bgp 200 0
*> 2.2.2.2/32 100.1.1.5 gei-0/0/0/2 ospf 110 1
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30 ︱Maintenance Experience Issue 276
*> 3.3.3.3/32 3.3.3.3 loopback1 address 0 0
*> 100.1.1.0/30 100.1.1.5 gei-0/0/0/2 ospf 110 2
*> 100.1.1.4/30 100.1.1.6 gei-0/0/0/2 direct 0 0
*> 100.1.1.6/32 100.1.1.6 gei-0/0/0/2 address 0 0
*> 172.16.0.0/24 100.1.1.5 gei-0/0/0/2 bgp 200 0
*> 172.16.1.0/24 100.1.1.5 gei-0/0/0/2 bgp 200 0
*> 172.16.2.0/24 100.1.1.5 gei-0/0/0/2 bgp 200 0
*> 172.16.3.0/24 100.1.1.5 gei-0/0/0/2 bgp 200 0
The above information shows that BGP
routes can be added to the local routing
forward table only when the synchronization
function of the BGP route on R3 is disabled. In
addition, during the EBGP route distribution
between R2 and R1, EBGP routes of other
ASs are added to the local routing forward
table no matter the BGP synchronization
function is disabled or not.
Instructor explanation: When the BGP
synchronization function is enabled, the BGP
router cannot notify the BGP routes learnt
from the IBGP neighbor to its own EBGP
neighbor. The BGP router notifies the BGP
routes to the EBGP router except that these
BGP routes exist in the IGP routing table.
The verification steps are as follows:
Configure the BGP on R3:
router bgp 200
no synchronization
redistribute connected
network 33.33.33.33 255.255.255.255
neighbor 2.2.2.2 remote-as 200
neighbor 2.2.2.2 activate
neighbor 2.2.2.2 next-hop-self
neighbor 2.2.2.2 update-source loopback1
! </BGP>
Configure the BGP on R2:
router bgp 200
neighbor 3.3.3.3 remote-as 200
neighbor 3.3.3.3 activate
neighbor 3.3.3.3 next-hop-self
neighbor 3.3.3.3 update-source loopback1
neighbor 100.1.1.1 remote-as 100
neighbor 100.1.1.1 activate
BGP routes on R2 are not added to the forwarding routing table. The details are as follows:
R2#show ip bgp route
Status codes: *-valid, >-best, i-internal, s-stale
Origin codes: i-IGP, e-EGP, ?-incomplete
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Data Products Special Issue Issue 1, 2013︱ 31
Dest NextHop Metric LocPrf RtPrf Path
*> 1.1.1.1/32 100.1.1.1 20 100 i
*i 3.3.3.3/32 3.3.3.3 100 200 ?
*i 33.33.33.33/32 3.3.3.3 100 200 i
*i 100.1.1.4/30 3.3.3.3 100 200 ?
*i 100.1.1.8/30 3.3.3.3 100 200 ?
*> 172.16.0.0/24 100.1.1.1 20 100 i
*> 172.16.1.0/24 100.1.1.1 20 100 i
*> 172.16.2.0/24 100.1.1.1 20 100 i
*> 172.16.3.0/24 100.1.1.1 20 100 i
R2#show ip forwarding route
IPv4 Routing Table:
status codes: *valid, >best
Dest Gw Interface Owner Pri Metric
*> 1.1.1.1/32 100.1.1.1 gei-0/0/0/1 bgp 20 0
*> 2.2.2.2/32 2.2.2.2 loopback1 address 0 0
*> 3.3.3.3/32 100.1.1.6 gei-0/0/0/2 static 1 0
*> 4.4.4.4/32 100.1.1.6 gei-0/0/0/2 ospf 110 2
*> 100.1.1.0/30 100.1.1.2 gei-0/0/0/1 direct 0 0
*> 100.1.1.2/32 100.1.1.2 gei-0/0/0/1 address 0 0
*> 100.1.1.4/30 100.1.1.5 gei-0/0/0/2 direct 0 0
*> 100.1.1.5/32 100.1.1.5 gei-0/0/0/2 address 0 0
*> 100.1.1.8/30 100.1.1.6 gei-0/0/0/2 ospf 110 2
*> 172.16.0.0/24 100.1.1.1 gei-0/0/0/1 bgp 20 0
*> 172.16.1.0/24 100.1.1.1 gei-0/0/0/1 bgp 20 0
*> 172.16.2.0/24 100.1.1.1 gei-0/0/0/1 bgp 20 0
*> 172.16.3.0/24 100.1.1.1 gei-0/0/0/1 bgp 20 0
At the same time, R2 cannot notify route 33.33.33.33 distributed by R2 to the EBGP
neighbor (R1) because the R2 routing table does not include route 33.33.33.33. This meets the
synchronization enabling rule.
The BGP table of R1 does not include route33.33.33.33:
R1(config)#show ip bgp route
Status codes: *-valid, >-best, i-internal, s-stale
Origin codes: i-IGP, e-EGP, ?-incomplete
Dest NextHop Metric LocPrf RtPrf Path
*> 1.1.1.1/32 1.1.1.1 0 0 i
*> 3.3.3.3/32 100.1.1.2 20 200 ?
*> 100.1.1.4/30 100.1.1.2 20 200 ?
*> 100.1.1.8/30 100.1.1.2 20 200 ?
*> 172.16.0.0/24 172.16.0.1 0 0 i
Maintenance Instances
32 ︱Maintenance Experience Issue 276
*> 172.16.1.0/24 172.16.1.1 0 0 i
*> 172.16.2.0/24 172.16.2.1 0 0 i
*> 172.16.3.0/24 172.16.3.1 0 0 i
If the IGP table of R3 includes the 33.33.33.33 network segment that is distributed by the
OSPF, add this network segment to R2, and then check whether R2 notifies route 33.33.33.33 to
R1.
R1#show ip forwarding route
IPv4 Routing Table:
status codes: *valid, >best
Dest Gw Interface Owner Pri Metric
*> 1.1.1.1/32 1.1.1.1 loopback1 address 0 0
*> 3.3.3.3/32 100.1.1.2 gei-0/0/0/1 bgp 20 0
*> 33.33.33.33/32 100.1.1.2 gei-0/0/0/1 bgp 20 0
*> 100.1.1.0/30 100.1.1.1 gei-0/0/0/1 direct 0 0
*> 100.1.1.1/32 100.1.1.1 gei-0/0/0/1 address 0 0
*> 100.1.1.4/30 100.1.1.2 gei-0/0/0/1 bgp 20 0
*> 100.1.1.8/30 100.1.1.2 gei-0/0/0/1 bgp 20 0
*> 172.16.0.0/24 172.16.0.1 loopback2 direct 0 0
*> 172.16.0.1/32 172.16.0.1 loopback2 address 0 0
*> 172.16.1.0/24 172.16.1.1 loopback3 direct 0 0
*> 172.16.1.1/32 172.16.1.1 loopback3 address 0 0
*> 172.16.2.0/24 172.16.2.1 loopback4 direct 0 0
*> 172.16.2.1/32 172.16.2.1 loopback4 address 0 0
*> 172.16.3.0/24 172.16.3.1 loopback5 direct 0 0
*> 172.16.3.1/32 172.16.3.1 loopback5 address 0 0
4 Conclusion
It is necessary to know the influence and
purpose on the current network when the
synchronization function of the EBGP or IBGP
is enabled or disabled.
The understanding on the no
synchronization command in the BGP is
divided into two parts:
(1) In the EBGP neighbor, after the no
synchronization command is executed, the
BGP router notifies the BGP routes learnt
from the IBGP neighbor to its EBGP neighbor
even if these routes do not exist in its own IGP
routing table.
(2) In the IBGP neighbor, after the no
synchronization command is executed, the
BGP router adds the BGP routes to the local
routing forward table instead of waiting for the
IGP synchronization.
After you configure the no
synchronization command in the BGP, you do
not need to execute the redistribut
bgp-int/bgp-ext command in the IGP (such as
OSPF).
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Data Products Special Issue Issue 1, 2013︱ 33
In most cases, the IBGP routes and the
IGP routes in the same AS are consistent.
Once a route of other AS is added, and the
EBGP neighbor is established, there are two
selections. One is to distribute the BGP route
to the IGP route protocol for the EBGP again,
for example, execute the redistribut
bgp-int/bgp-ext command in the OSP, and the
other is to execute the no synchronization
command for the EBGP or IBGP. In most
networks, the synchronization function is
disabled by default.
The above details how to disable the
synchronization function. In fact, it describes
how the BGP route establishes an IP routing
forward table.
The following two methods can be used
to establish an IP routing table.
(1) Add an EBGP route to an IP routing
table
1) In the BGP topology table, the EBGP
route is considered as the optimized route.
2) If the same route that is learnt from
other IGP or static routes exists, the
administrative distance of BGP external
routes is shorter than that of other routes. By
default, the administrative distance of BGP
external routes is 20, which is shorter than
that of other dynamic routes (except that the
administrative distance of the EIGRP
summary route is 5).
In this case, the operation that R2 obtains
inter-domain EBGP routes is not affected by
the synchronization function of R2. All routes
are added to the IP routing forward table.
(2)Add the IBGP route to an IP routing
table
1) This route must be the optimized BGP
route.
2) Compared with other routes, this route
is the optimized route based on the
administrative distance.
3) For the IBGP route, the IGP
synchronization function must be considered.
The IGP synchronization function in the router
is enabled by default. When the IGP
synchronization function is enabled, the BGP
notifies route information to another ASs and
adds the routes to the IP routing forwarding
table till the IGP propagates the route
information to its AS successfully. When all
BGP routers in the AS are connected, the
synchronization function can be disabled.
On R3, the BGP routes are not added to
the IP routing forward table because R2 is
always waiting for the IGP synchronization. In
most BGP networks, all IBGP are connected
(or using RR), so the synchronization function
is disabled. However, the synchronization
function is enabled by default (the
synchronization function of CISCO is disabled
by default).
FAQ
34 ︱Maintenance Experience Issue 276
FAQ
Question: How does M6000 allocate ports to users when M6000 acts as the BAR and the nat444 service is enabled?
Answer:
The M6000 allocates ports to users with
two modes, dynamic mode and static mode.
Dynamic mode: After a user dials a
number successfully, the M6000
allocates initial ports to the user.
cgn-pool test poolid 1
pool-type port-range 128
After the user dials a number
successfully, the M6000 allocates 1-128
ports to the user. When the user
downloads software through the BT or
performs other on-line services, initial
ports are insufficient. In this case, M6000
continues allocating ports to the user.
128 ports are allocated to the user once a
time, and the corresponding log is
generated.
Static mode: After a user dials a number
successfully, the M6000 allocates fixed
ports to the user. After all ports are used
up, the M6000 will not allocate ports.
Question: What is the difference between Address Translation and Address Proxy?
Answer:
Both the address translation technology
and the address agent technology provide a
private address to access the Internet. The
difference is the location in the TCP/IP
protocol stack. The address translation
technology works in the network layer, while
the address agent technology works in the
application layer.
The address translation technology is
transparent to all applications, but the address
agent technology must specify the IP address
of an agent server in the application program.
For example, when you access a Website
through the address translation technology,
you do not need to configure the browser. If
you access a Website through the address
Proxy technology, you need to configure the
IP address of the Proxy in the browser. If the
Proxy only supports the HTTP protocol, you
can access the Website only through the
address Proxy technology, and you cannot
access the Website through the FTP. The
above information shows that the address
translation technology is better than the
address Proxy technology because you do
not need to configure the browser.
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Data Products Special Issue Issue 1, 2013︱ 35
However, the address translation
technology cannot provide the authentication
based on the user name and the password.
With the address Proxy technology, only the
user whose user name and password are
authenticated can access the Internet.
Question: What is the size of the local-buffer configured in the RADIUS charging? Can you configure the size? What should you do when the buffer is full?
Answer:
The size of the local-buffer is 3072
messages, and the size cannot be configured.
When the buffer is full, new messages can be
saved to the buffer only after the messages
stored in the buffer are sent out.
Question: In the dual-server hot-backup system, the VRRP is used to determine the active/standby server. When the heartbeat line is broken, both servers are active VRRP. Whether the user online is affected when two BRASs are in active status?
Answer:
If the heartbeat line of the VRRP is
broken, the heartbeat line will be in init status.
Servers are independent, so the user online is
not affected. After one server does not
receive VRRP messages, it will become the
active server after a period of time. In this
case, maybe two servers are in active status.
In this case, the server that gives a response
to the user packet first forwards user data.
The backup mode of the device is similar to
the cold standby.
Address: ZTE Plaza, No.55, Hi-tech Road South, Shenzhen, P.R.China Post code: 518057
Customer Support Hotline: +86-755-26771900 Tel:+86-755-26776049Fax: +86-755-26772236Customer Support Email: doc@zte.com.cnTechnical Support Website: http://ensupport.zte.com.cnPublication Date: April 10, 2013