39-3
Catalyst 3750-E and 3560-E Switch Software Configuration Guide
OL-9775-02
Chapter39 Configuring IPv6 Unicast Routing
Understanding IPv6
For more information about IPv6 address formats, address types, and the IPv6 packet header, go to
“Implementing Basic Connectivity for IPv6” chapter of the Cisco IOS IPv6 Configuration Library at this
URL:
http://www.cisco.com/en/US/products/sw/iosswrel/ps5187/products_configuration_guide_chapter0918
6a00801d65f5.html
In the “Information About Implementing Basic Connect ivity for IPv6” section, these sections apply to
the Catalyst 3750-E or 3560-E switch:
•IPv6 Address Formats
•IPv6 Address Type: Unicast
•IPv6 Address Output Display
•Simplified IPv6 Packet Header
Supported IPv6 Unicast Routing Features
These sections describe the IPv6 protocol (RFC 2460) features supported by the switch:
•128-Bit Wide Unicast Addresses, page 39-3
•Path MTU Discovery for IPv6 Unicast, page 39-4
•ICMPv6, page 39-4
•Neighbor Discovery, page 39-4
•IPv6 Stateless Autoconfiguration and Duplicate Address Detection, page 39-5
•IPv6 Applications, page 39-5
•Dual IPv4 and IPv6 Protocol Stacks, page 39-6
Support on the switch includes expanded address capability, header format simp lification, improved
support of extensions and options, and hardware parsing of the extension header. The switch supports
hop-by-hop extension header packets, which are routed or bridged in software.
The switch provides IPv6 routing capability over native Ethernet Inter-Switch Link (ISL) or 802.1Q
trunk ports for static routes, Routing Information Protocol (RIP) for IPv6 (RFC 2080), and Open
Shortest Path First (OSPF) Version 3 protocol (RFC 2740). It supports up to 16 equal-cost routes and
can forward IPv4 and IPv6 frames simultaneously at line rate.
Note The selection of the equal-cost routes on Catalyst 3 750-E and 3560-E switches is the same as that on
Catalyst 3750 and 3560 switches except for the differen ces summarized in the Cisco Software Activation
and Compatibility Document on Cisco.com.

128-Bit Wide Unicast Addresses

The switch supports aggregatable global unicast addresses and link-local unicast addresses (RFC 2373).
It does not support site-local unicast addresses.
•Aggregatable global unicast addresses are IPv6 addresses from the aggregatable global unicast
prefix. The address structure enables strict aggregation of routing prefixes and limits th e number of
routing table entries in the global routing table. These addresses are used on links that are aggregated
through organizations and eventually to the Internet service provider.