CCIE Candidate

Okay, I think I’m officially finished with my IPv6 review.  I finally understand the different tunnel types…what each requires and where each one fits in an IPv6 implementation.  (I did manage to resist the urge to jump ahead to a mock lab)

All tunnel types are utilized to provide IPv6 connectivity over an IPv4 network.  I started typing all of the details about each different tunnel type and then realized I could just post the figures from the Cisco Doc site.  These tables are from the Cisco IOS IPv6 Configuration Guide, Release 12.4

Table 1 describes the use of each tunnel.  Very important words in the [Suggested Use] cell are point-to-point (Manual & GRE) & point-to-multipoint (IPv4 Compatible (deprecated), ISATAP, 6to4) THIS IS POINT-to-POINT NON-BROADCAST which is important for IPv6 routing protocols.

Since ISATAP & 6to4 tunnels are point-to-point non-broadcast, neighbors statements must be made for routing protocols that use multicast updates / hellos.  I’m assuming that I can skip EIGRP for IPv6 since it is not on the blueprint?

• RIPng doesn’t work over these tunnel types - (as far as I can tell) no neighbor statement available to unicast updates
• OSPFv3 - tunnel interface - network type must be point-to-multipoint non-broadcast OR non-broadcast & neighbor statement must configured on tunnel interface - i.e. ipv6 ospf neighbor FE80::5EFE:101:101

The second table, Table 2,  shows what each tunnel requires for configuration.  Notice that tunnel destination is not configured explicitly for ISATAP and 6to4 as they’re determined based on the destination IPv6 address in the packet sent to the tunnel interface.

This method of reading the Cisco Documentation site along with Narbik’s workbooks is working very well.  I didn’t quite understand the reasoning behind each tunnel type until I began going through the documentation line-by-line.  My next two topics for today are NAT and IP Services.  I have also scheduled some rack time on ccie2be.com racks to get ready for my IE mock lab next week.

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