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Cisco Catalyst Blade Switch 3130 for Dell Software Configuration Guide
OL-13270-01
Chapter39 Configuring IPv6 Unicast Routing
Understanding IPv6
•In addition to the normal SPAN and RSPAN limitations defined in the software configuration guide,
these limitations are specific to IPv6 packets:
–
When you egress RSPAN IPv6-routed packets, the source MAC address in the SPAN output
packet can be corrupted.
–
When you egress RSPAN IPv6-routed packets, the destination MAC address can be corrupted.
Normal traffic is not affected.
•The switch cannot apply QoS classification, or policy-based routing on source-routed IPv6 packets
in hardware.
•The switch cannot generate ICMPv6 Packet Too Big messages for multicast packets.
IPv6 and Switch Stacks
The switch supports IPv6 forwarding across the stack much the same as with IPv4 unicast routing. The
stack master runs the IPv6 unicast routing protocols and computes the routing tables. Using distributed
CEF (dCEF), the stack master downloads the routing table to the stack member switches. The member
switches receive the tables and install IPv6 routes into hardware for hardware forwarding.
Note To route IPv6 packets in a stack, all switches in the stack should be running the advanced IP services
feature set.
If a new switch becomes the stack master, the new master recomputes the IPv6 routing tables and
distributes them to the member switches. While the new stack master is elected and is resetting, the
switch stack does not forward IPv6 packets. If a new switch becomes the stack master, the stack MAC
address also changes. When the IPv6 address of the stack is specified with an extended universal
identifier (EUI) by using the ipv6 address ipv6-prefix/prefix length eui-64 interface configuration
command, the address is based on the interface MAC add res s, a nd c han ging t he MAC addre ss ch an ge s
the IPv6 address. See the “Configuring IPv6 Addressing and Enabling IPv6 Routing” section on
page 39-13.
Note If you configure the persistent MAC addres s feat ur e on the stac k an d th e st ack m aste r ch ange s, the sta ck
MAC address does not change for approximately four minutes. If the previous stack master rejoins the
stack as a member switch during that time period, the stack MAC address remains the MAC address of
the previous stack master. See the “Enabling Persistent MAC Address” section on page5-21 in
Chapter5, “Managing Switch Stacks.”
These are the functions of IPv6 stack master and members:
•Stack master:
–
runs IPv6 routing protocols
–
generates routing tables
–
distributes CEFv6 routing tables to stack members that use dCEFv6
–
runs IPv6 host functionality and IPv6 applications
•Stack member (must be running the advanced IP services feature set):
–
receives CEFv6 routing tables from the stack master
–
programs the routes into hardware