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Connecting Intel Switch to 2nd GBIC port

Dear all,

Is it possible to connect an Intel Switch GBIC port across to GBIC port 2 on a 2950G, then connect GBIC port 1 (on the same device) to another 2950G's port 2, which has port 1 connected via a Gigastack to a stack of 2950G's ? Would this need any additional configuration ?


Intel_SW > SwitchA_GBIC2 > SwitchA_GBIC1 >SwitchB_GBIC2 > SwitchB_GBIC1 > Gigastack



  • Other Network Infrastructure Subjects

Re: Connecting Intel Switch to 2nd GBIC port

Yes, you can daisy-chain the Intel switch to the Cisco 2950G "A" with a point-to-point Gigabit connection. You may have to tell the interface to "speed nonegotiate" and then subsequently set flowcontrol manually. (Cisco GBIC ports run at speed 1000, duplex full; but I think they try to exchange flow control information with neighboring switches, unless you tell them not to.)

Maybe, you might need additional configuration; I assume you mean on the Cisco switch connected to the Intel one. Besides the above, you may also have to manually specify whether the Cisco "A" switch treats the connection to the Intel switch as a VLAN access link (all Intel switch ports effectively belong to the same single Cisco VLAN), or a VLAN trunk link (where multiple VLAN ports on the Intel merge and tag traffic onto the Gigabit connection to the Cisco.)

If you specify the switchport mode manually as either access or trunk, then there's no need for the Cisco to try and negotiate the switchport mode with the Intel; so you may want to run "switchport nonegotiate" to suppress Dynamic Trunk Protocol (DTP) frames.

Then there's always STP. It looks like your switch daisy-chain is not exceeding the default STP network diameter of 7 switches in a row, that could require you to increase STP timers. Although I don't know how big your GigaStack is, and whether there are any other switches, or where you may have redundant links. If you have no redundant links from the Intel to any of the Cisco switches, then you could even configure "spanning-tree portfast" on the Cisco switch "A" side, to get the port forwarding as soon as link is connected. Not sure if the Intel has an equivalent setting, though.

Also, search the NetPro forums here for "nonegotiate" and maybe "Intel" or "3Com", to see other people's experiences connecting to non-Cisco switches.

Hope this helps.

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