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Converting CS11501 bridge interfaces into trunks.

Hello all. Is it possible to convert previously bridge Fast Ethernet interface on the 11501 CSS to be trunk interface?

I have run of out of interfaces to bridge VLAN's so I want to trunk them to the CSS.

The 6509 core switch is the L2 switch that bridges traffic to the CSS in dual-arm configuration (client/server side VLAN interfaces).

Can I just use one FastEthernet interface on the CSS and turn it into a trunk interface that will pass both client and server side traffic? Or do I need two trunk interfaces that will trunk server side and client side traffic separately?

Thank you.



Re: Converting CS11501 bridge interfaces into trunks.

HI Dimitry,

The CSS software has a dependency when using the trunk command. For trunking to be enabled, all VLAN bridging commands for any active VLAN must first be disabled for the Gigabit Ethernet or Fast Ethernet interface by using the no bridge vlan, no bridge port-priority, no bridge state, and no bridge pathcost commands. If you do not disable VLAN bridging on an interface, the CSS software instructs you to do so.

First of all take backup of your CSS config file before doing any changes.

The CSS provides Ethernet interfaces (ports) that enable you to connect servers, PCs, routers, and other devices to the CSS.

Using the bridge command, you bridge (assign) the interfaces to a specific Virtual LAN (VLAN). Each VLAN circuit requires an IP address. Assigning an IP address to each VLAN circuit allows the CSS to route Ethernet interfaces from VLAN to VLAN.

Using the trunk command, you can assign multiple VLANs to a CSS Ethernet interface port (Fast Ethernet port or Gigabit Ethernet port). A trunk is a point-to-point link carrying the traffic of several VLANs. The advantage of a trunk is to save ports when creating a link between two devices implementing VLANs, typically two switches. A trunk bundles virtual links over one physical link. The unique physical link between the two CSSs is able to carry traffic for the specified VLANs.

Here is the link where you can find a configuration example:

802.1q Trunking on the CSS 11x00 Configuration Example

Sachin Garg

Senior Specialist Security

HCL Comnet Ltd.

A-10, Sector 3, Noida- 201301


Mob: +91-9911757733


New Member

Re: Converting CS11501 bridge interfaces into trunks.

Thank you Sachin for the information.

What about the second part of my question, would I need two trunk interfaces for the client and server side or just one interface where both client and server side VLANS are trunked together?

Thank you.


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