Cisco 6503 User Manual download pdf (Page 16)

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SRM and IP Multicast

With SRM, the VLAN interfaces on the nondesignated router are in a down state. Even after a failover, these interfaces will

not move into an up state until the supervisor engine veriﬁes that the VLAN has at least one connected physical interface in

the forwarding state. This interruption causes the supervisor engine to delete all multicast entries in the PFCx and this disrupts

multicast forwarding. As an enhancement to the original SRM implementation, Cisco Catalyst OS release 7.1 provides

support for IP Multicast stateful redundancy. When SRM is enabled in Cisco Catalyst OS version 7.1, the multicast ﬂows are

preserved during a failover.

Supervisor and MSFC Failover Tests

A test environment was created to demonstrate sample high-availability switchover scenarios and record the corresponding

failover times. The test setup included one Cisco Catalyst 6509 chassis with dual supervisor engine 2 line cards running Cisco

Catalyst OS version 7.2.2 or MSFC2 hardware running Cisco IOS Software Release 12.1(11b)E4. These tests were intended

to be basic and easily demonstrated. The testing mechanism was pings between two end devices connected directly to the

switch. Spanning-Tree was enabled on the ports in use for all scenarios. Tests were initiated by resetting the switch supervisor

engine. Each scenario was tested eight times and the results were averaged.

Layer 2 Failover

For Layer 2 trafﬁc between two end stations within the same VLAN , the failover resulted in a one or two ping timeout

(approximately one- or two-second failover time).

Note:

This test can be performed on a supervisor engine without an MSFC.

Layer 3 Failover

For Layer 3 trafﬁc, a common test environment was created for measuring the supervisor or MSFC failover of a single Cisco

Catalyst 6500 Series conﬁgured ﬁrst with DRM and then with SRM. The two pinging devices were placed in separate VLANs.

The basic software conﬁguration included enabling the High Availability feature on the Cisco Catalyst OS and then either

DRM or SRM redundancy in the Cisco IOS Software on the MSFC2. The complete conﬁgurations are shown below.

SRM

hostname SRM

redundancy

high-availability

single-router-mode

interface Vlan20

ip address 10.20.1.3 255.255.255.0

no ip redirects

interface Vlan30

ip address 10.30.1.3 255.255.255.0

no ip redirects

end

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Cisco 6503 User Manual Page 16