© 2001, Cisco Systems, Inc. Signaling Mechanism. © 2001, Cisco Systems, Inc. QOS v1.0—7-2...

transcript

Signaling Mechanism

ObjectivesObjectives

Upon completing this module, you will be able to: • Describe RSVP

• Configure RSVP

• Describe and configure RSVP on shared media using SBM

• Monitor and troubleshoot RSVP

Resource Reservation Protocol (RSVP)

Upon completing this lesson, you will be able to: • Describe RSVP

• Configure RSVP

Resource Reservation ProtocolResource Reservation Protocol

• RSVP is a protocol used to reserve resources in a path between a source and a destination.

• RSVP signals all network devices that a certain application needs certain QoS guarantees.

• RSVP requires applications to initiate the request.

• RSVP by itself does not provide any guarantees.

• An RSVP-interoperable QoS mechanism (WFQ, CBWFQ) must be used to implement guarantees according to RSVP reservations.

End-to-End RSVPEnd-to-End RSVP

• All network devices have to be enabled for RSVP.

• Each network device determines whether it has enough resources.

requestrequest requestrequest requestrequest requestrequest

reservereservereservereservereservereservereservereserve

Local Admission

Control

Local Admission

Control

Local Admission

Control

Pass-Through RSVPPass-Through RSVP

• Part of the network may not support RSVP.

• Best-effort delivery is used in those parts.

requestrequest

reservereservereservereserve

reservereserve

Local Admission

Control

Best-EffortForwarding

RSVPNot

Enabled

RSVPNot

Enabled

requestrequest requestrequest

Local Admission

Control

Local Admission

Control

Pass-Through RSVPwith Class of ServicePass-Through RSVPwith Class of Service

• Part of the network may not support RSVP.• Mark RSVP flows with a class of service

marker (e.g., IP Precedence or DSCP).• Make sure that the core provides guarantees

to the RSVP class.

requestrequest

reservereserve

Local Admission

Control

Local Admission

Control

RSVPNot

Enabled

RSVPNot

Enabled

requestrequest requestrequest

Mark RSVP flow with DSCP.

Local Admission

Control

Class-BasedGuarantee

RSVP ApplicationsRSVP Applications

• RSVP is used for applications for which bandwidth and delay-related guarantees are necessary.

• Typical applications are:

–Voice over IP (Cisco phones, Microsoft NetMeeting, etc.)

–MPLS traffic engineering

Configuring Simple RSVPConfiguring Simple RSVP

ip rsvp bandwidth [total-BW [per-flow-BW]]ip rsvp bandwidth [total-BW [per-flow-BW]]

Router(config-if)#

• Set the amount of reservable bandwidth (total-BW) and the maximum per-flow reservable bandwidth (per-flow-BW) in kbps

• Both default to 75% of the configured bandwidth• Total reservable bandwidth cannot exceed 75% of the

configured bandwidth

bandwidth bandwidthbandwidth bandwidth

Router(config-if)#

• Set the interface bandwidth in kbps• This value should reflect the real bandwidth of the link

Configuring Proxy RSVPConfiguring Proxy RSVP

ip rsvp sender session-IP sender-IP protocol dport sport src-hop-IP src-intf bandwidth burst ip rsvp sender session-IP sender-IP protocol dport sport src-hop-IP src-intf bandwidth burst

Router(config)#

• Simulates a host sending a PATH message• Generates a PATH message on behalf of a host or an

application

ip rsvp reservation session-IP sender-IP protocol dport sport next-hop-IP next-hop-intf {ff | se | wf} {rate | load} bw burst ip rsvp reservation session-IP sender-IP protocol dport sport next-hop-IP next-hop-intf {ff | se | wf} {rate | load} bw burst

Router(config)#

• Simulates a host sending an RESV message• Generates an RESV message on behalf of a host or

an application

RSVP Admission ControlRSVP Admission Control

• RSVP has two tasks:

–Determine if there are enough available resources

–Determine if the application in question is allowed access to these resources

• RSVP-enabled devices keep track of existing reservations locally.

• RSVP-enabled devices can off-load the authorization part of admission control to central servers (COPS).

Common Open Policy ServiceCommon Open Policy Service

• COPS allows a more centralized approach to building RSVP-enabled networks (more scalable).• COPS provides additional control over who can

reserve what.

requestrequest requestrequest requestrequest requestrequest

reservereservereservereservereservereservereservereserve

Local Admission

Control

Remote Admission Control

Local Admission

Control

Policy Decision Point (PDP)

Policy Enforcement Point (PEP)

Configuring RSVP for COPSConfiguring RSVP for COPS

ProcessLocally?ProcessLocally?

Reject?Reject?

ProcessMessageProcessMessage

Reject Message(Send an error message to the

source.)

Yes Yes

LocalOverride?

YesDefaultLocal

Policy?

DefaultLocal

Policy?

ProcessRemotely?Process

Remotely?AskPDP

Reject?Reject?

Yes DefaultReject?DefaultReject?

ip rsvp policy local acl

ip rsvp policy localip rsvp policy local local-override

DefaultRemotePolicy?

Configuring RSVP for COPS (cont.)

ProcessLocally?ProcessLocally? Reject?Reject?

ProcessMessageProcessMessage

source.)

Yes Yes

LocalOverride?

YesDefaultLocal

Policy?

DefaultLocal

Policy?

ProcessRemotely?Process

Remotely?AskPDP

Reject?Reject?

YesDefaultReject?DefaultReject?

ip rsvp policy cops acl servers

ip rsvp policy default-reject

DefaultRemotePolicy?

ip rsvp policy cops servers

RSVPExample

interface Serial0/0 bandwidth 256 ip address 10.5.8.65 255.255.255.252 encapsulation ppp fair-queue 64 256 20 ip rtp header-compression ip rsvp bandwidth 160

interface Serial0/0 bandwidth 128 ip address 10.10.3.33 255.255.255.252 encapsulation ppp fair-queue 64 256 10 ip rtp header-compression ip rsvp bandwidth 80

RSVP with COPSExample

interface Serial0/0 bandwidth 2048 ip address 10.1.1.1 255.255.255.252 encapsulation ppp fair-queue 64 256 100 ip rsvp bandwidth 512!ip rsvp policy cops 100 servers 10.100.1.1 10.101.1.1ip rsvp policy default-rejectip rsvp policy cops minimalip rsvp policy cops timeout 600ip rsvp policy cops report-all!access-list 100 permit udp any any

COPS(PEP)

COPS(PDP)

Monitoring and Troubleshooting RSVP

show ip rsvp installed [detail]show ip rsvp installed [detail]

Router#

• Lists installed reservations per interface

Router#show ip rsvp installedRSVP:Ethernet2/1BPS To From Protoc DPort Sport Weight Conversation44K 145.20.0.202 145.10.0.201 UDP 1000 1000 0 26444K 145.20.0.202 145.10.0.201 UDP 1001 1001 13 26698K 145.20.0.202 145.10.0.201 UDP 1002 1002 6 2651K 145.20.0.202 145.10.0.201 UDP 10 10 0 264RSVP:Serial3/0 has no installed reservations

Monitoring and Troubleshooting RSVP (cont.)

show ip rsvp installed [detail] [interface]show ip rsvp installed [detail] [interface]

Router#

Router#show ip rsvp installed detailRSVP:Ethernet2/1 has the following installed reservationsRSVP Reservation. Destination is 145.20.0.202, Source is 145.10.0.201, Protocol is UDP, Destination port is 1000, Source port is 1000 Reserved bandwidth:44K bits/sec, Maximum burst:1K bytes, Peak rate: 44K bits/sec QoS provider for this flow:WFQ. Conversation number:264. Weight:0 (PQ) Conversation supports 1 reservations Data given reserved service:316 packets (15800 bytes) Data given best-effort service:0 packets (0 bytes) Reserved traffic classified for 104 seconds Long-term average bitrate (bits/sec):1212 reserved, 0M best-effortRSVP Reservation. Destination is 145.20.0.202, Source is 145.10.0.201, Protocol is UDP, Destination port is 1001, Source port is 1001 Reserved bandwidth:44K bits/sec, Maximum burst:3K bytes, Peak rate: 44K bits/sec QoS provider for this flow:WFQ. Conversation number:266. Weight:13 Conversation supports 1 reservations Data given reserved service:9 packets (450 bytes) Data given best-effort service:0 packets (0 bytes) Reserved traffic classified for 107 seconds Long-term average bitrate (bits/sec):33 reserved, 0M best-effort...

Monitoring and Troubleshooting RSVP (cont.)

show ip rsvp reservation [detail]show ip rsvp reservation [detail]

Router(config)#

• List RSVP reservations

show ip rsvp request [detail]show ip rsvp request [detail]

Router(config)#

• List pending RSVP requests

Monitoring and Troubleshooting RSVP with COPS

show ip rsvp policy [{cops | local} [acl]]show ip rsvp policy [{cops | local} [acl]]

Router#

Router#show ip rsvp policy copsCOPS/RSVP settings: Generate reports for all decisions Do not query PDP for error messagesCOPS/RSVP entry. ACLs: 100PDPs: 10.100.1.1 10.101.1.1Current state: ConnectedCurrently connected to PDP 10.100.1.1, port 0

COPS/RSVP entry. ACLs: 101 PDPs: 10.102.1.1 Current state: In reconnect loop wait Reconnect timer is 960 seconds

Router#show ip rsvp policy copsCOPS/RSVP settings: Generate reports for all decisions Do not query PDP for error messagesCOPS/RSVP entry. ACLs: 100PDPs: 10.100.1.1 10.101.1.1Current state: ConnectedCurrently connected to PDP 10.100.1.1, port 0

COPS/RSVP entry. ACLs: 101 PDPs: 10.102.1.1 Current state: In reconnect loop wait Reconnect timer is 960 seconds

• Lists all policies

Monitoring and Troubleshooting RSVP with COPS (cont.)

show cops serversshow cops servers

Router#

Router#show cops serversCOPS SERVER: Address: 10.100.1.1. Port: 3288. State: 0. Keepalive: 120 sec Number of clients: 1. Number of sessions: 1.

COPS CLIENT: Client type: 1. State: 0.

Router#show cops serversCOPS SERVER: Address: 10.100.1.1. Port: 3288. State: 0. Keepalive: 120 sec Number of clients: 1. Number of sessions: 1.

COPS CLIENT: Client type: 1. State: 0.

• Lists all COPS servers

SummarySummary

Upon completing this lesson, you should be able to:• Describe Resource Reservation Protocol

(RSVP)

• Configure RSVP

Lesson ReviewLesson Review

1. What is RSVP used for?

2. Does RSVP provide QoS guarantees?

3. What QoS mechanism should be used to provide QoS guarantees to RSVP reservations?

4. What are the benefits of using COPS with RSVP?

Subnet Bandwidth Management

Upon completing this lesson, you will be able to: • Describe Subnet Bandwidth Management

• Configure SBM

• Monitor and troubleshoot RSVP with SBM

Subnet Bandwidth ManagementSubnet Bandwidth Management

• RSVP manages unidirectional reservation of resources.

• RSVP on shared media can result in oversubscription.

• SBM is an add-on to RSVP on shared media to prevent oversubscription.

Without SBMWithout SBM

• Both routers are within the 75 percent reservable limit.• Total reserved bandwidth is 13 Mbps (above Ethernet bandwidth).• Ethernet should be treated carefully because it is impossible to

achieve 100 percent use (collisions can occur, depending on implementation).

Ethernet

Ethernet bandwidth 10Mbps7.5 Mbps reservable

Reserve 6 Mbps

Reserve 7 MbpsReserve 7 Mbps

0 Mbps booked7.5 Mbps free

7 Mbps booked512 kbps free

With SBMWith SBM

7 Mbps booked512 kbps free

Reserve 6 MbpsReserve 6 MbpsReserve 6 Mbps

Reserve 6 Mbps

One of the routers on the segment is elected to be the designated subnet bandwidth manager (DSBM).The shared media is effectively transformed into a star of point-to-point links.

ErrorError

DSBM ElectionDSBM Election

• The DSBM is elected based on the DSBM priority.

• Each DSBM candidate advertises its priority in the range of 64 to 128.

• The candidate with the highest priority is elected to be the DSBM.

• RSVP-enabled devices can participate in subnet bandwidth management without being DSBM candidates.

Configuring DSBMConfiguring DSBM

ip rsvp dsbm candidate priorityip rsvp dsbm candidate priority

Router(config-if)#

• Configures the router to bid in the election of the DSBM• Default priority is 64

ip rsvp dsbm non-resv-send-limit {burst | max-unit | min-unit | peak | rate} valueip rsvp dsbm non-resv-send-limit {burst | max-unit | min-unit | peak | rate} value

Router(config)#

• The NonResvSendLimit object specifies how much traffic can be sent onto a managed segment without a valid RSVP reservation

• All values are unlimited by default

SBMExample

interface Ethernet0/0 ip address 10.1.1.1 255.255.255.0 ip rsvp bandwidth 7500 7500 ip rsvp dsbm candidate 100 ip rsvp dsbm non-resv-send-limit rate 100 ip rsvp dsbm non-resv-send-limit burst 1000 ip rsvp dsbm non-resv-send-limit peak 100!

Monitoring and Troubleshooting SBM

show ip sbm [detail]show ip sbm [detail]

Router#

• Lists interfaces where SBM is active• The detail option displays detailed information about local

configuration and the DSBM configuration

Router#show ip rsvp sbmInterface DSBM Addr DSBM Priority DSBM Candidate My PriorityEt0/0 10.1.1.1 100 yes 100Et0/1 10.1.2.1 100 yes 100Router#show ip rsvp sbm detailInterface:Ethernet0/0Local Configuration Current DSBM IP Address:10.1.1.1 IP Address:10.1.1.1 DSBM candidate:yes I Am DSBM:yes Priority:100 Priority:100 Non Resv Send Limit Non Resv Send Limit Rate:100 Kbytes/sec Rate:100 Kbytes/sec Burst:1000 Kbytes Burst:1000 Kbytes Peak:100 Kbytes/sec Peak:100 Kbytes/sec Min Unit:unlimited Min Unit:unlimited Max Unit:unlimited Max Unit:unlimited

SummarySummary

Upon completing this lesson, you should be able to:• Describe Subnet Bandwidth Management

• Configure SBM

• Monitor and troubleshoot RSVP with SBM

Lesson ReviewLesson Review

1. What is the purpose of subnet bandwidth management?

2. How do routers on a common subnet communicate reservation requests?

3. What is a DSBM?

4. How do routers elect a DSBM?

Module SummaryModule Summary

Upon completing this module, you should be able to:• Describe Resource Reservation Protocol

(RSVP)

• Configure RSVP

• Describe and configure RSVP on shared media using subnet bandwidth management (SBM)

© 2001, Cisco Systems, Inc. Signaling Mechanism. © 2001, Cisco Systems, Inc. QOS v1.0—7-2...

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