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Archive for the ‘Cisco Certification: BCMSN’ Category

Cisco switches: Classic STP -> RSTP -> MST

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To better use switch connections that are otherwise blocked by STP, I setup 5 switches (2 distribution and 2+1 access) to support 7 VLANs with redundant links for fault tolerance.
Traditional CSTP provided for convergence after a link failed, in 52 seconds. RSTP amazingly reduced that to sub-second convergence. MST maintained that, but the lab will continue next time to carry the 7 VLANs over two different virutual switch topologies. (I did NOT use VTP with this work.) Read the rest of this entry »

Written by scottledyard

2007, March 18th at 1:37 pm

Cisco EtherChannel and dual links

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Last week I explored STP with a trio of switches connected in a ring. Ditto yesterday, but I added double cables between 4 ports of two of the switches and enabled a EtherChannel link. As with most labs, the core part was easy and I chewed through a lot of time trying to ping simply because I hadn’t issued a no shutdown on VLAN1!

Found a good recap of what I did with EtherChannel at this web site. He needs to point out that the cost goes from 12 up to 19 when he disconnects a line.
And at this site are some neat ideas for additional switching labs. PLUS a way to zap any vlans but VLAN1:

conf t
delete flash:vlan.dat

Anyway, here’s some documentation of what went on. Read the rest of this entry »

Written by scottledyard

2007, March 11th at 2:48 pm

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