Dynamic Routing Protocols with IPv6: Configuration, Verification, and Troubleshooting - AMA

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Ask Me Anything Forum

In this event we will answer all your questions related to dynamic routing protocols with IPv6 configuration, verification, troubleshooting, and general best current practices. All questions regarding design, in-depth mechanics, and features of the Routing Information Protocol for IPv6, OSPFv3, ISIS, EIGRPv6, and BGP are welcome.

To participate in this event, please use the  button below to ask your questions

Ask questions from Wednesday, April 14 to Tuesday, April 27, 2021

Featured Experts

Gary Bolivar is a Senior Technical Consulting Engineer in the Cisco HTTS (High Touch Technical Support) for Routing and Switching. He specializes in solving advanced routing protocol problems for corporate networks, Service providers , and data centers for customers primarily in North America. He has worked with multiple Cisco platforms and routing protocols for the last seven years. He currently holds dual CCIE, Routing & Switching and Service Provider among others, and a degree in computer science. Gary is also passionate about network automation and scripting.

Harold Ritter is a Senior Technical Leader in the Cisco Advanced Services Group. He has many years of experience as a network architect and works closely with business segment customers and service providers. Among his duties, he is responsible for deploying technologies such as MPLS, IPv6, multicast, and routing protocols in general. He has dual CCIE (Routing & Switching and Service Provider) certifications and regularly conducts presentations on various IPv6 topics, primarily at Cisco Live events.

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[gbolivar]

Hi Nono82,

6PE and 6VPE allow us to run IPv6 over an IPv4-only MPLS core where we use dual stack PE routers.

This allows service providers to offer IPv6 to their customers without making major changes to the core of their MPLS network.

The main difference between 6PE and 6VPE will be:

• 6PE uses the global IPv6 routing table on the PE routers.
• 6VPE uses VRFs on the PE routers (MPLS VPN).

Thank you,

Gary 

Senior Technical Consulting Engineer

[Harold Ritter]

Hi Nono,

Both 6PE and 6VPE transport IPv6 traffic over the MPLS core. The MPLS core does not need to be running IPv6 at all (except for the PE). IPv6 traffic will be encapsulated in an MPLS LSP and forwarded to the relevant egress PE.

The difference between the two is that 6PE works using the global routing table on the PE, whereas 6VPE will perform the IPv6 lookup from a VRF routing table on the PE. So 6VPE is equivalent to IPv4 L3VPN. 

Regards,

[John Ventura]

Hello,

What are the OSPFv3 LSA types?

Thanks,

John V

[gbolivar]

Hi John,

Much of OSPF version 3 is the same as in OSPF version 2. OSPFv3, which is described in RFC 5340, expands on OSPF version 2 to provide support for IPv6 routing prefixes and the larger size of IPv6 addresses.

Here are the OSPFv3 LSA types.

LSA Types for OSPFv3

The following list describes LSA types, each of which has a different purpose:

• Router LSAs (Type 1)--Describes the link state and costs of a router's links to the area. These LSAs are flooded within an area only. The LSA indicates if the router is an Area Border Router (ABR) or Autonomous System Boundary Router (ASBR), and if it is one end of a virtual link. Type 1 LSAs are also used to advertise stub networks. In OSPFv3, these LSAs have no address information and are network-protocol-independent. In OSPFv3, router interface information may be spread across multiple router LSAs. Receivers must concatenate all router LSAs originated by a given router when running the SPF calculation.

• Network LSAs (Type 2)--Describes the link-state and cost information for all routers attached to the network. This LSA is an aggregation of all the link-state and cost information in the network. Only a designated router tracks this information and can generate a network LSA. In OSPFv3, network LSAs have no address information and are network-protocol-independent.

• Interarea-prefix LSAs for ABRs (Type 3)--Advertises internal networks to routers in other areas (interarea routes). Type 3 LSAs may represent a single network or a set of networks summarized into one advertisement. Only ABRs generate summary LSAs. In OSPFv3, addresses for these LSAs are expressed as prefix, prefix length instead of address, mask. The default route is expressed as a prefix with length 0.

• Interarea-router LSAs for ASBRs (Type 4)--Advertises the location of an ASBR. Routers that are trying to reach an external network use these advertisements to determine the best path to the next hop. Type 4 LSAs are generated by ABRs on behalf of ASBRs.

• Autonomous system external LSAs (Type 5)--Redistributes routes from another autonomous system, usually from a different routing protocol into OSPFv3. In OSPFv3, addresses for these LSAs are expressed as prefix, prefix length instead of address, mask. The default route is expressed as a prefix with length 0.

• Link LSAs (Type 8)--Have local-link flooding scope and are never flooded beyond the link with which they are associated. Link LSAs provide the link-local address of the router to all other routers attached to the link, inform other routers attached to the link of a list of prefixes to associate with the link, and allow the router to assert a collection of Options bits to associate with the network LSA that will be originated for the link.

• Intra-Area-Prefix LSAs (Type 9)--A router can originate multiple intra-area-prefix LSAs for each router or transit network, each with a unique link-state ID. The link-state ID for each intra-area-prefix LSA describes its association to either the router LSA or the network LSA and contains prefixes for stub and transit networks.

Regards,

Gary

[Olipo]

How do you configure RIP for IPv6?

Regards, Olipo

[gbolivar]

Hello Olipo,

IPv6 RIP works 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-devices multicast group address FF02::9 as the destination address.

- Make sure Ipv6 unicast-routing is enabled.

- Configure IPv6 RIP on the interface.

Configuration:

1.    enable

2.    configure terminal

3.    ipv6 unicast-routing

4.    interface type number

5.    ipv6 rip name enable

Thank you,

Gary

[Olipo]

Hi Gary,

Thank you for your reply ! One last question...

How do you configure RIP for IPv6 ? Any additional material / reference you may provide will be appreciated !

Best regards

[gbolivar]

Hi Olipo,

Here is the configuration guide for more information.

https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/iproute_rip/configuration/xe-3s/asr1000/ip6-rip-xe.html#GUID-71B88028-5ADE-443D-90AD-BDB1136C850B 

Thanks,

Gary