[f-nsp] Difficulties with STP and VLANs

Zurek, Patrick pzurek at uillinois.edu
Tue Mar 28 15:25:20 EST 2006


Hi everyone,
I'm running a pair of ServerIron chassis, and a FastIron II+ and 800.  Each FI has several VLANs on it.  STP is enabled and part of the network forms a loop with the STP weights adjusted so that the trunk between the FI800 and FI2p on VLAN 10 only comes up during a failure (reliability issues with the SIs prompted this).  The ServerIrons each connect to VLAN 10 on each FastIron and connect again to VLAN 165 on the same switch.  Each FI is running multiple instances of spanning tree - each SI is running a single instance.

This is the logical layout:

       ISP
      /   \
FI800 -- FI2p
|	    |                 vlan 10
SI1      S12                   ~~~~~~~~
|	    |                 vlan 165
FI800 -- FI2p
|	    |
hosts    hosts

The first strange thing I notice is that both VLAN 1 (one) and VLAN 165 share the same bridge address (each FI is different from the other though).  Is this normal?

The second, and more important issue, is that last week, there was an outage lasting several hours.  It all started after a STP TC was executed.  No changes were made to the network to prompt that and it happened after this configuration was running for several months.  In my haste to correct the problem, I didn't take accurate notes, and my memory is hazy.  But at one point, I powered one of the ServerIrons off. Then, I noticed that the other SI's ports were BLOCKING.  Rebooting the switches didn't help, I was only able to recover by disabling and reenabling STP on the switches.  I know the details are sparse so I don't expect much in the way of help, however, I was told by someone that they experienced a similar problem before when connecting a ServerIron to the same FastIron twice, on different VLANS -- something to do with the STP BPDUs being received by the same physical switch twice caused problems.

I can't figure out what prompted the TC, nor why the switches stopped forwarding traffic after that.  I don't recall which ports were BLOCKING, if any, initially after the problem started.  Later, even after one of the SIs was powered off, thereby removing any physical loop in the network, certain interfaces were still BLOCKING.  I'm sure my understanding of this is flawed and any advice or recommendation based on such a bad description would be greatly appreciated!


Thanks,
Pat


PS I've attached the logs during the first hour of the problem and a snippet of show span from FI800:

Global STP (IEEE 802.1D) Parameters:
VLAN Root             Root Root Prio Max He- Ho- Fwd Last     Chg  Bridge
 ID   ID              Cost Port rity Age llo ld  dly Chang    cnt  Address
                                Hex  sec sec sec sec sec
   1 800000e052d5c800 0    Root 8000 20  2   1   15  676420   0    00e052d5c800

VLAN Root             Root Root Prio Max He- Ho- Fwd Last     Chg  Bridge
 ID   ID              Cost Port rity Age llo ld  dly Chang    cnt  Address
                                Hex  sec sec sec sec sec
 165 800000048071ef00 4    3/7  8000 20  2   1   15  674707   2    00e052d5c800

VLAN Root             Root Root Prio Max He- Ho- Fwd Last     Chg  Bridge
 ID   ID              Cost Port rity Age llo ld  dly Chang    cnt  Address
                                Hex  sec sec sec sec sec
  10 800000048071ef00 12   1/3  8000 20  2   1   15  674817   5    00e052d5c802


Mar 20 16:21:27 SIGT1, L4 server eisweb7 is down
Mar 20 16:21:27 SIGT1, L4 server eisweb7 port 80 is down due to server-down
Mar 20 16:21:28 SIGT1, L4 server eisweb3 is down
Mar 20 16:21:28 SIGT1, L4 server eisweb3 port 80 is down due to server-down
Mar 20 16:21:28 SIGT1, L4 server eisweb4 is down
Mar 20 16:21:28 SIGT1, L4 server eisweb4 port 80 is down due to server-down
Mar 20 16:21:28 SIGT1, L4 server eisweb5 is down
Mar 20 16:21:28 SIGT1, L4 server eisweb5 port 80 is down due to server-down
Mar 20 16:21:28 SIGT1, L4 server eisweb6 is down
Mar 20 16:21:28 SIGT1, L4 server eisweb6 port 80 is down due to server-down
Mar 20 16:21:28 SIGT1, L4 server eisweb port 80 is down. SERVICE DOWN
Mar 20 16:21:32 FastIronIIPlus, VLAN 165 Bridge is RootBridge: 800000e052d5c846 (MsgAgeExpiry)
Mar 20 16:21:34 FastIron800, VLAN 165 Bridge is RootBridge: 800000048071ef26 (MsgAgeExpiry)
Mar 20 16:21:34 FastIronIIPlus, VLAN 165 New RootBridge: 800000048071ef26 RootPort: 3/7 (BpduR
cvd)
Mar 20 16:21:34 SIGT1, VLAN 1 Bridge is RootBridge: 8000000cdb5d3920 (MsgAgeExpiry)
Mar 20 16:33:16 FastIronIIPlus, NTP server 130.126.24.24 failed to respond
Mar 20 16:33:31 FastIronIIPlus, NTP server 130.126.24.44 failed to respond
Mar 20 17:03:16 FastIronIIPlus, NTP server 130.126.24.24 failed to respond
Mar 20 17:03:31 FastIronIIPlus, NTP server 130.126.24.44 failed to respond
Mar 20 17:22:55 FastIronIIPlus, Interface ethernet 3/7, state down
Mar 20 17:22:55 FastIronIIPlus, VLAN 10 Bridge is RootBridge: 800000e052d5c807 (PortDown)
Mar 20 17:22:55 FastIronIIPlus, VLAN 165 Bridge is RootBridge: 800000e052d5c846 (PortDown)
Mar 20 17:22:55 FastIronIIPlus, Interface ethernet 3/8, state down
Mar 20 17:22:59 FastIronIIPlus, VLAN 10 Port 3/7 STP State -> LISTENING (MakeFwding)
Mar 20 17:22:59 FastIronIIPlus, VLAN 165 Port 3/7 STP State -> LISTENING (MakeFwding)
Mar 20 17:22:59 FastIronIIPlus, Interface ethernet 3/7, state up
Mar 20 17:22:59 FastIronIIPlus, Interface ethernet 3/8, state up
Mar 20 17:23:14 FastIronIIPlus, VLAN 165 Port 3/7 STP State -> LEARNING (FwdDlyExpiry)
Mar 20 17:23:14 FastIronIIPlus, VLAN 10 Port 3/7 STP State -> LEARNING (FwdDlyExpiry)
Mar 20 17:23:19 FastIronIIPlus, Interface ethernet 3/7, state down
Mar 20 17:23:19 FastIronIIPlus, VLAN 10 Port 3/7 STP State -> DISABLED (PortDown)
Mar 20 17:23:19 FastIronIIPlus, VLAN 165 Port 3/7 STP State -> DISABLED (PortDown)
Mar 20 17:23:19 FastIronIIPlus, Interface ethernet 3/8, state down
Mar 20 17:23:25 FastIronIIPlus, VLAN 10 Port 3/7 STP State -> LISTENING (MakeFwding)
Mar 20 17:23:25 FastIronIIPlus, VLAN 165 Port 3/7 STP State -> LISTENING (MakeFwding)
Mar 20 17:23:25 FastIronIIPlus, Interface ethernet 3/7, state up
Mar 20 17:23:25 FastIronIIPlus, Interface ethernet 3/8, state up
Mar 20 17:23:32 FastIronIIPlus, VLAN 165 New RootBridge: 800000048071ef26 RootPort: 3/7 (BpduR
cvd)
Mar 20 17:23:32 FastIronIIPlus, VLAN 10 New RootBridge: 800000048071ef26 RootPort: 3/7 (BpduRc
vd)
Mar 20 17:23:40 FastIronIIPlus, VLAN 10 Port 3/7 STP State -> LEARNING (FwdDlyExpiry)
Mar 20 17:23:40 FastIronIIPlus, VLAN 165 Port 3/7 STP State -> LEARNING (FwdDlyExpiry)
Mar 20 17:23:55 FastIronIIPlus, VLAN 10 Port 3/7 STP State -> FORWARDING (FwdDlyExpiry)
Mar 20 17:23:55 FastIronIIPlus, VLAN 10 Port 3/7 Bridge TC Event (FwdDlyExpiry)
Mar 20 17:23:55 FastIronIIPlus, VLAN 165 Port 3/7 STP State -> FORWARDING (FwdDlyExpiry)
Mar 20 17:23:55 FastIronIIPlus, VLAN 165 Port 3/7 Bridge TC Event (FwdDlyExpiry)




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