[c-nsp] STP issue

[P.A]

We have an Ethernet ring with 6 cisco 3500 switches. "Spanning tree 1 is
executing the IEEE compatible Spanning Tree protocol"

The root switch of this ring is connected to a cisco 6500. The cisco 6500 is
not participating in this spanning tree ring. I simply have a routed
interface from the 6500 to the 3500 root switch.

 

6500 interface:

 

FastEthernet1/5 is up, line protocol is up

  Internet address is 10.10.10.1/24

  Broadcast address is 255.255.255.255

  Address determined by setup command

  MTU is 1500 bytes

  Helper address is not set

  Directed broadcast forwarding is disabled

  Secondary address 209

  Secondary address 209

  Secondary address 209

 

Everything on the ring works as expected, its blocking and forwarding in the
right places etc. The issue sometimes is when there is a topology change in
the ring the 6500 can't ping certain ring switches usually the ring switch
which had the backup port but sometimes other switches also. On the 6500 I
noticed that the the arp entry age for those switch ips is usually set to 0
and it takes a long time for the 6500 to ping those switches.  When
everything is up and running the 6500 can ping any ring switch ip with zero
issues but as soon as there is a change on the ring things to go bad but
again again within the ring all is well.

 

I was thinking that even if I have a routed interface on the 6500 towards
the 3500 root switch that it would route the 1st packet leaving the 6500 to
the 3500 root and then the 3500 would use the L2 header to switch the
packet. This does seem to work but then again when a topo change occurs the
6500 starts to have issues.

 

 

I was thinking of involving the 6500 in the spanning tree ring and making it
the root, this should probably solve my issues but I was wondering if anyone
has any idea what the problem might be what I  need to solve it.

 

On another note, the 6500 is running rst-pvst and the 3500 are running ieee
stp, I shouldn't see any issues between the two flavors correct?

Also the 3500 are using the regular vlan1 interface and I wanted to create
vlan interface on the 6500 of 105, will this cause issues.

 

 

Thanks very much, paul