[c-nsp] VTP/STP/TRUNK

[Jyotirmay Samanta (Gmail)]

Hi! Shaun,
                Actually there is no limit for STP interfaces but there is a limit on STP instances. In C3750 the limit is 128 & in C2950 the limit is 64. Here u are reaching the limit in 2950, so your most logical approach would be to move towards MSTP.

Good resource for MSTP can be found at - http://www.cisco.com/en/US/partner/products/hw/switches/ps4324/products_configuration_guide_chapter09186a00804d784c.html

Thanks & Regards,
 
Jyotirmay Samanta
 
Network Engineering Group
Sify Ltd. Tidel Park - Chennai
Mobile : +91 9884088678
  ----- Original Message ----- 
  From: Shaun 
  To: cisco-nsp at puck.nether.net 
  Sent: Tuesday, December 20, 2005 1:55 AM
  Subject: Re: [c-nsp] VTP/STP/TRUNK


  I'm not sure what the limit is for STP interfaces on the 3750, i'm sure it's 
  much higher than my 2950's.  The error i'm seeing (max STP) is on the 2950's 
  not the 3750 so i'm hitting the limit on them.  I beleive i have around 70 
  vlans or so.  I'll have to read up on MSTP, i know nothing about it.  Any 
  good docs?

  Shaun



  "Bostjan Fele" <Bostjan.Fele at avtenta.si> wrote in message 
  news:17F17D9EE77ED94ABD148A8408732D27287768 at atena.fog.local...
  > Hi,
  >
  > If you have a lot of VLANs (more than switch can have STP instance for) 
  > migrate to MSTP config from PVST+ spanning tree. I had similar problems 
  > that VLANs were not pruned even when pruning was enabled and no access 
  > ports were on edge switch...
  >
  > Regards,
  > Bostjan
  >
  > -----Original Message-----
  > From: cisco-nsp-bounces at puck.nether.net 
  > [mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Shaun
  > Sent: Sunday, December 18, 2005 9:55 AM
  > To: cisco-nsp at puck.nether.net
  > Subject: [c-nsp] VTP/STP/TRUNK
  >
  > I have a 3750 connected to multiple 2950G's, 3750 is running as VTP Server
  > V1 with pruning enabled.  The 2950G's are trunked to the 3750 and run VTP 
  > as a client.  One of my 2950G's recently through this error at me.
  >
  > %SPANTREE_VLAN_SW-2-MAX_INSTANCE: Platform limit of 64 STP instances 
  > exceeded. No instance created for VLAN153 (port Fa0/1).
  >
  > I understand the error, STP is enabled on too many interfaces for this 
  > device but this switch only has probably different vlans assigned to it.
  > After further investigation I found that a sh int <port> trunk on both the 
  > 2950 and the 3750 showed different info.
  >
  > 2950G
  >    Port        Vlans in spanning tree forwarding state and not pruned
  >    Fa0/1       1-2,20,50,60-61,95-119,121-153,155-158
  >
  > 3750
  >    Port        Vlans in spanning tree forwarding state and not pruned
  >    Fa1/0/13    1-2,60,97-99,115,120,122,133,137-138,141-142,144,153
  >
  > As you can see the 2950 is showing more vlans on the trunked port than the 
  > 3750 is showing.  Is this normal?  Shouldn't they match?
  >
  > Just to clarify I'm not restricting vlans on the trunked interfaces on the 
  > 3750.
  >
  > I also ran this same test on a different 2950 that's trunked to the 3750 
  > and the results where backwards on that switch.  The 2950 showed fewer 
  > vlans on the trunked port than the 3750 showed..
  >
  > I verified I have the right ports to the right switches by doing a sh cdp 
  > nei
  >
  > Thanks in advance.
  >
  > -- 
  >
  > ~Shaun
  >
  >
  >
  > _______________________________________________
  > cisco-nsp mailing list  cisco-nsp at puck.nether.net 
  > https://puck.nether.net/mailman/listinfo/cisco-nsp
  > archive at http://puck.nether.net/pipermail/cisco-nsp/
  >
  > _______________________________________________
  > cisco-nsp mailing list  cisco-nsp at puck.nether.net
  > https://puck.nether.net/mailman/listinfo/cisco-nsp
  > archive at http://puck.nether.net/pipermail/cisco-nsp/
  > 



  _______________________________________________
  cisco-nsp mailing list  cisco-nsp at puck.nether.net
  https://puck.nether.net/mailman/listinfo/cisco-nsp
  archive at http://puck.nether.net/pipermail/cisco-nsp/