Cisco Cisco 1700 2600 3600 3700 Series VPN Module White Paper

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By configuring at least one of the supervisor uplink ports as a VSL port, the system will be able to initialize the VSL

without having to initialize any other line cards. Therefore, it is beneficial and recommended to use at least one of

the supervisor module 10 Gigabit Ethernet uplink ports for the VSL.

Two-Port VSL Using Supervisor-Engine Uplinks

In this scenario, the two members of the Cisco Virtual Switching System are connected through a 2-port VSL

EtherChannel. The VSL is formed out of the two 10 Gigabit Ethernet uplink ports on the supervisor module

installed in Slot 5 of each chassis.

Figure 7. VSL Formed Using Two 10 Gigabit Ethernet Supervisor Ports

A two-port VSL using supervisor ports offers:

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A minimum of two links providing protection from port and SFP failures

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Diverse physical paths, to protect from physical layer outages

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No requirement for additional VSL-capable line cards (minimal cost)

If additional bandwidth is needed for the VSL, additional 10 Gigabit ports from supported line cards can be used.

Up to eight ports per port channel can be added, the same as with any other port channel interface.

Four-Port VSL Using Quad-Sup Uplink Forwarding

The Supervisor 720-10 G supports the Quad-Sup Uplink Forwarding

feature, which allows for a redundant in-

chassis supervisor module. Again, it is recommended to build the VSL with at least one port from each supervisor

module. If desired, you can use all the 10 Gigabit ports from the supervisor modules for the VSL. With this

configuration, you should cross-connect one port form each supervisor to one port on each supervisor on the peer

chassis. This will help ensure an active VSL port member local to the active supervisor, regardless of any

supervisor module failure.

More details on the Quad-Sup Uplink Forwarding feature are provided in the High Availability section of this paper.