Routing in IPv6

Static Routing

RIP

EIGRP

OSPF

RIP for IPv6

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RIP for IPv6 Overview IPv6 RIP functions the same and offers the same benefits as RIP in IPv4. RIP

enhancements for IPv6, detailed in RFC 2080, include support for IPv6 addresses and prefixes, and the use of the all-RIP-routers multicast group address FF02::9 as the destination address for RIP update messages.

New commands specific to RIP in IPv6 were also added to the Cisco IOS command-line interface (CLI).

Each IPv6 RIP process maintains a local routing table - Routing Information Database (RIB).

The IPv6 RIP RIB contains a set of best-cost IPv6 RIP routes learned from all its neighboring networking devices.

If IPv6 RIP learns the same route from two different neighbors, but with different costs, it will store only the lowest cost route in the local RIB.

The RIB also stores any expired routes that the RIP process is advertising to its neighbors running RIP. IPv6 RIP will try to insert every non-expired route from its local RIB into the master IPv6 RIB. If the same route has been learned from a different routing protocol with a better administrative distance than IPv6 RIP, the RIP route will not be added to the IPv6 RIB but the RIP route will still exist in the IPv6 RIP RIB.

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Implementing RIP for IPv6

Three Steps: Create the routing process Enable the routing process on interfaces Customize the routing protocol for your particular

network.

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Step 1. Enabling IPv6 RIP

Before configuring the router to run IPv6 RIP, globally enable IPv6 using the ipv6 unicast-routing global configuration command, and enable IPv6 on any interfaces on which IPv6 RIP is to be enabled.

STEPS 1. enable

2. configure terminal

3. interface type number

4. ipv6 rip name enable

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Step 2. Customizing IPv6 RIPCommand or Action Purpose

ipv6 router rip word Router(config)# ipv6 router rip cisco

Configures an IPv6 RIP routing process and enters router configuration mode for the IPv6 RIP routing process. Use the word argument to identify a specific IPv6

RIP routing process. maximum-paths number-paths Router(config-router)# maximum-paths 1

(Optional) Defines the maximum number of equal-cost routes that IPv6 RIP can support. The number-paths argument is an integer from 1

to 64. The default for RIP is four paths.

ipv6 rip name default-information {only | originate} [metric metric-value] Router(config-if)# ipv6 rip cisco default-information originate

(Optional) Originates the IPv6 default route (::/0) into the specified RIP routing process updates sent

out of the specified interface.

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Verifying IPv6 RIP Configuration and Operation

A user may want to check IPv6 RIP configuration and operation.

Some of the following scenarios may occur for which a user can then enable the following show and debug commands: "Why isn't a certain route appearing in my IPv6 routing table?" "Am I receiving routes via RIP?" "Is a certain route being filtered?" "Someone at a route site told me that I am not advertising a

certain route. True?"

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Verifying IPv6 RIP Configuration and Operation

Command or Action Purposeshow ipv6 rip [name] [database | next-hops] Router> show ipv6 rip cisco database

(Optional) Displays information about current IPv6 RIP processes. In this example, IPv6 RIP process database information is displayed for the specified IPv6 RIP process.

show ipv6 route [ipv6-address | ipv6-prefix/prefix-length | protocol | interface-type interface-number] Router> show ipv6 route rip

(Optional) Displays the current contents of the IPv6 routing table. In this example, only IPv6 RIP routes are displayed.

debug ipv6 rip [interface-type interface-number] Router# debug ipv6 rip

(Optional) Displays debugging messages for IPv6 RIP routing transactions.

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show ipv6 rip Command: Example

Router> show ipv6 rip

RIP process "cisco", port 521, multicast-group FF02::9, pid 62 Administrative distance is 120. Maximum paths is 1 Updates every 5 seconds, expire after 15 Holddown lasts 10 seconds, garbage collect after 30 Split horizon is on; poison reverse is off Default routes are generated Periodic updates 223, trigger updates 1

Interfaces: Ethernet0/0

Redistribution: Redistributing protocol bgp 65001 route-map bgp-to-rip

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show ipv6 rip Command: Example Output information about a specified IPv6 RIP process database is

displayed using the show ipv6 rip command with the name argument and the database keyword.

In the following output for the IPv6 RIP process named cisco, timer information is displayed, and route 2001:0db8::16/64 has a route tag set:

Router> show ipv6 rip cisco database RIP process "cisco", local RIB

2001:0db8::/64, metric 2

Ethernet0/0/FE80::A8BB:CCFF:FE00:B00, expires in 13 secs 2001:0db8::/16, metric 2 tag 4, installed

Ethernet0/0/FE80::A8BB:CCFF:FE00:B00, expires in 13 secs 2001:0db8:1::/16, metric 2 tag 4, installed

Ethernet0/0/FE80::A8BB:CCFF:FE00:B00, expires in 13 secs 2001:0db8:2::/16, metric 2 tag 4, installed

Ethernet0/0/FE80::A8BB:CCFF:FE00:B00, expires in 13 secs ::/0, metric 2, installed

Ethernet0/0/FE80::A8BB:CCFF:FE00:B00, expires in 13 secs

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show ipv6 route Command: Example

Router> show ipv6 route rip

IPv6 Routing Table - 17 entries Codes: C - Connected, L - Local, S - Static, R - RIP, B - BGP

U - Per-user Static route

I1 - ISIS L1, I2 - ISIS L2, IA - ISIS interarea O - OSPF intra, OI - OSPF inter, OE1 - OSPF ext 1, OE2 - OSPF ext 2

R 2001:0db8:1::/32 [120/2] via FE80::A8BB:CCFF:FE00:A00, Ethernet0/0

R 2001:0db8:2::/32 [120/2] via FE80::A8BB:CCFF:FE00:A00, Ethernet0/0

R 2001:0db8:3::/32 [120/2] via FE80::A8BB:CCFF:FE00:A00, Ethernet0/0

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Configuration Examples for IPv6 RIPipv6 router rip cisco maximum-paths 1 redistribute bgp 65001 route-map bgp-to-rip  distribute-list prefix-list eth0/0-in-flt in Ethernet0/0 ! interface Ethernet0/0 ipv6 address 2001:0db8::/64 eui-64 ipv6 rip cisco enable ipv6 rip cisco default-information originate ! ipv6 prefix-list bgp-to-rip-flt seq 10 deny 2001:0db8:3::/16 le 128 ipv6 prefix-list bgp-to-rip-flt seq 20 permit 2001:0db8:1::/8 le 128 ! ipv6 prefix-list eth0/0-in-flt seq 10 deny ::/0 ipv6 prefix-list eth0/0-in-flt seq 15 permit ::/0 le 128 ! route-map bgp-to-rip permit 10 match ipv6 address prefix-list bgp-to-rip-flt set tag 4

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Enabling RIPng in Router3 with the Advertisement of the Default Route

EIGRP for IPv6

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EIGRP for IPv6 Overview EIGRP for IPv6 is directly configured on the interfaces over which it

runs. This feature allows EIGRP for IPv6 to be configured without the use of a global IPv6 address. There is no network statement in EIGRP for IPv6.

In per-interface configuration at system startup, if EIGRP has been configured on an interface, then the EIGRP protocol may start running before any EIGRP router mode commands have been executed.

An EIGRP for IPv6 protocol instance requires a router ID before it can start running.

EIGRP for IPv6 has a shutdown feature. The routing process should be in "no shutdown" mode in order to start running.

When a user uses passive-interface configuration, EIGRP for IPv6 does not need to be configured on the interface that is made passive.

EIGRP for IPv6 provides route filtering using the distribute-list prefix-list command. Use of the route-map command is not supported for route filtering with a distribute list.

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Implementing EIGRP for IPv6 Enabling EIGRP for IPv6 on an Interface Configuring the Percentage of Link Bandwidth Used Configuring Summary Aggregate Addresses Configuring EIGRP Route Authentication Adjusting the Interval Between Hello Packets in EIGRP for

IPv6 Adjusting the Hold Time in EIGRP for IPv6 Customizing an EIGRP for IPv6 Routing Process Monitoring and Maintaining EIGRP

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Enabling EIGRP for IPv6 on an Interface

Command or Action Purpose

ipv6 unicast-routing

Router(config)# ipv6 unicast-routing

Enables the forwarding of IPv6 unicast datagrams.

ipv6 enable

Router(config-if)# ipv6 enable

Enables IPv6 processing on an interface that has not been configured with an explicit IPv6 address.

ipv6 eigrp as-number

Router(config-if)# ipv6 eigrp 1

Enables EIGRP for IPv6 on a specified interface.

ipv6 router eigrp as-number Router(config)# ipv6 router eigrp 1

Enters router configuration mode and creates an EIGRP for IPv6 routing process.

router-id {ip-address | ipv6-address}

Router(config-router)# router-id 10.1.1.1

Enables the use of a fixed router ID.

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Configuring the Percentage of Link Bandwidth Used

By default, EIGRP packets consume a maximum of 50 percent of the link bandwidth, as configured with the bandwidth interface configuration command.

STEPS 1. interface  type number 2. bandwidth {kbps | inherit [kbps]} 3. ipv6 bandwidth-percent eigrp as-number

percent

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Configuring Summary Aggregate Addresses

Steps:1. interface  type number

2. ipv6 summary-address eigrp as-number ipv6-address [admin-distance]

Router(config)# interface FastEthernet 0/ 0 Router(config-if)# ipv6 summary-address eigrp 1

2001:0DB8:0:1::/64

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Configuring EIGRP Route Authentication - Overview EIGRP route authentication provides Message

Digest 5 (MD5) authentication of routing updates from the EIGRP routing protocol.

The MD5 keyed digest in each EIGRP packet prevents the introduction of unauthorized or false routing messages from unapproved sources.

Each key has its own key identifier, which is stored locally.

The combination of the key identifier and the interface associated with the message uniquely identifies the authentication algorithm and MD5 authentication key in use.

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Configuring EIGRP Route Authentication interface  type number ipv6 authentication mode eigrp as-number md5 ipv6 authentication key-chain eigrp as-number key-chain exit key chain name-of-chain key key-id key-string text accept-lifetime start-time {infinite | end-time | duration seconds} send-lifetime start-time {infinite | end-time | duration seconds}

Example: Router(config)# interface FastEthernet 0/0 Router(config-if)# ipv6 authentication mode eigrp 1 md5 Router(config-if)# ipv6 authentication key-chain eigrp 1 chain1 Router(config-if)# exit Router(config)# key chain chain1 Router(config-keychain)# key 1 Router(config-keychain-key)# key-string chain 1 Router(config-keychain-key)# accept-lifetime 14:30:00 Jan 10 2006 duration 7200 Router(config-keychain-key)# send-lifetime 15:00:00 Jan 10 2006 duration 3600

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Monitoring and Maintaining EIGRP

Use of clear and debug commands helps users monitor and maintain their EIGRP for IPv6 environments.

Deleting Entries from EIGRP for IPv6 Routing Tables clear ipv6 eigrp [as-number] [neighbor [ipv6-address |

interface-type interface-number]] Router# clear ipv6 eigrp neighbor 3FEE:12E1:2AC1:EA32

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Adjusting the Interval Between Hello Packets in EIGRP for IPv6 Routing devices periodically send hello packets to each other to

dynamically learn of other routers on their directly attached networks. This information is used to discover neighbors and to learn when

neighbors become unreachable or inoperative. By default, hello packets are sent every 5 seconds. The exception is on low-speed, nonbroadcast multiaccess (NBMA)

media, where the default hello interval is 60 seconds. Low speed is considered to be a rate of T1 or slower, as specified with

the bandwidth interface command. The hold time is advertised in hello packets and indicates to neighbors

the length of time they should consider the sender valid. The default hold time is three times the hello interval, or 15 seconds. For slow-speed NBMA networks, the default hold time is 180 seconds.

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Adjusting the Interval Between Hello Packets in EIGRP for IPv6

interface  type number ipv6 hello-interval eigrp as-number

seconds Router(config)# interface FastEthernet 0/0 Router(config)# ipv6 hello-interval eigrp 1 10

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Adjusting the Hold Time in EIGRP for IPv6

On very congested and large networks, the default hold time might not be sufficient time for all routers to receive hello packets from their neighbors.

In this case, you may want to increase the hold time. ipv6 hold-time eigrp as-number seconds

Router(config-if)# ipv6 hold-time eigrp 1 40

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Customizing an EIGRP for IPv6 Routing Process

After you have enabled EIGRP for IPv6 on a specific interface, you can configure an EIGRP for IPv6 routing process.

The following optional tasks provide information on how to configure an EIGRP for IPv6 routing process to suit your needs: Logging EIGRP Neighbor Adjacency Changes Configuring Intervals Between Neighbor Warnings

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Logging EIGRP Neighbor Adjacency Changes

You can enable the logging of neighbor adjacency changes to monitor the stability of the routing system and to help you detect problems.

By default, adjacency changes are not logged. Use the following task to enable such logging:

interface  type number ipv6 router eigrp as-number log-neighbor-changes

Router(config)# interface FastEthernet 0/0 Router(config-if)# ipv6 router eigrp 1 Router(config-router)# log-neighbor-changes

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Configuring Intervals Between Neighbor Warnings

When neighbor warning messages occur, they are logged by default.

Use the following task to configure the interval between neighbor warning messages. interface  type number ipv6 router eigrp as-number log-neighbor-warnings [seconds]

Router(config)# interface FastEthernet 0/0 Router(config-if)# ipv6 router eigrp 1 Router(config-router)# log-neighbor-warnings 300

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Debugging Commands to Troubleshoot an EIGRP for IPv6 Environment

debug eigrp fsm debug eigrp neighbor [siatimer] [static] debug eigrp packet debug eigrp transmit [ack] [build] [detail] [link] [packetize]

[peerdown] [sia] [startup] [strange] debug ipv6 eigrp [as-number] [neighbor ipv6-address |

notification | summary]

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Configuring EIGRP to Establish Adjacencies on an Interface

ipv6 unicast-routing

interface e0

  ipv6 enable

  ipv6 eigrp 1

  no shutdown

!

ipv6 router eigrp 1

router-id 10.1.1.1

no shutdown