03-08-2012 08:06 AM - edited 03-07-2019 05:26 AM
Hello
I have a strange one here, anyone seen this before or any idea what is going on?
Thanks
Anthony
core01#show spanning-tree vlan 8
VLAN0008
Spanning tree enabled protocol rstp
Root ID Priority 24592
Address 000d.292b.7100
Cost 16
Port 641 (Port-channel1)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32776 (priority 32768 sys-id-ext 8)
Address 000d.292b.7100
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 14400 sec
Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi7/5 Desg FWD 19 128.389 P2p
Po1 Root FWD 3 128.641 P2p
Po8 Desg FWD 3 128.648 P2p
gpl-1-core01#show int gi1/1
GigabitEthernet1/1 is up, line protocol is up (connected)
Hardware is Gigabit Ethernet Port, address is 000d.292b.7100 (bia 000d.292b.7100)
MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec,
reliability 255/255, txload 80/255, rxload 58/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Full-duplex, 1000Mb/s, link type is auto, media type is 1000BaseSX
input flow-control is on, output flow-control is on
ARP type: ARPA, ARP Timeout 04:00:00
Last input 00:00:51, output never, output hang never
Last clearing of "show interface" counters never
Input queue: 0/2000/0/0 (size/max/drops/flushes); Total output drops: 93249
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 230598000 bits/sec, 53254 packets/sec
5 minute output rate 451592000 bits/sec, 60020 packets/sec
120048852136 packets input, 57061049922532 bytes, 0 no buffer
Received 8722380322 broadcasts (119867518 multicasts)
0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 input packets with dribble condition detected
164441471676 packets output, 174372748376360 bytes, 0 underruns
0 output errors, 0 collisions, 1 interface resets
0 babbles, 0 late collision, 0 deferred
0 lost carrier, 0 no carrier
0 output buffer failures, 0 output buffers swapped out
gpl-1-core01#show int gi2/1
GigabitEthernet2/1 is up, line protocol is up (connected)
Hardware is Gigabit Ethernet Port, address is 000d.292b.7102 (bia 000d.292b.7102)
MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec,
reliability 255/255, txload 82/255, rxload 15/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Full-duplex, 1000Mb/s, link type is auto, media type is 1000BaseSX
input flow-control is on, output flow-control is on
ARP type: ARPA, ARP Timeout 04:00:00
Last input 00:00:54, output never, output hang never
Last clearing of "show interface" counters 6w4d
Input queue: 0/2000/0/0 (size/max/drops/flushes); Total output drops: 3851
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 62623000 bits/sec, 24796 packets/sec
5 minute output rate 324902000 bits/sec, 35409 packets/sec
86375616789 packets input, 43280325517602 bytes, 0 no buffer
Received 6065659196 broadcasts (1749732733 multicasts)
0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 input packets with dribble condition detected
119236932961 packets output, 144710052143142 bytes, 0 underruns
0 output errors, 0 collisions, 4 interface resets
0 babbles, 0 late collision, 0 deferred
0 lost carrier, 0 no carrier
0 output buffer failures, 0 output buffers swapped out
gpl-1-core01#show spann
gpl-1-core01#show spanning-tree root port
VLAN0001 Port-channel1
VLAN0005 Port-channel1
VLAN0007 Port-channel1
VLAN0008 Port-channel1
VLAN0016 This bridge is root
VLAN0020 This bridge is root
VLAN0101 This bridge is root
VLAN0102 This bridge is root
VLAN0103 This bridge is root
VLAN0104 This bridge is root
VLAN0105 Port-channel1
VLAN0106 This bridge is root
VLAN0108 Port-channel1
VLAN0109 Port-channel1
VLAN0110 Port-channel1
VLAN0111 Port-channel1
VLAN0120 This bridge is root
VLAN0121 Port-channel1
VLAN0150 This bridge is root
VLAN0151 Port-channel1
VLAN0181 Port-channel1
VLAN0184 This bridge is root
VLAN0194 This bridge is root
VLAN0196 This bridge is root
VLAN0999 This bridge is root
03-08-2012 08:13 AM
Can you post your spanning-tree config? There are multiple vlans on the port-channel that doesn't believe it's the root. Are you splitting vlans among switches because it believes that the mac address 000d.292b.7100 is the root.
03-08-2012 08:44 AM
I don't think it is the root bridge on VLAN 8. Go to the switch that is connected to Po1 and do a show spanning-tree vlan 8. You will find that that is not the root bridge either: it will have a cost of 13, at least lower than the one you are on now.
Then follow the VLAN 8 root port on that switch to the next switch in line, and do the same. You will find the root cost decreases with each step. Eventually you will find the switch that really is the root. Then you can work out why it it the root.
Kevin Dorrell
Luxembourg
03-09-2012 06:23 AM
Thank you for your response. I have attached a diagram.
Basically, we have a riverbed in place as an inline device on one of the switches in the LAN. If I enable the trunk link between wansw01 and wansw02 we lose all connectivity on vlan 8. The config for the 2 ports attached to the Riverbed is below.
Please note that vlan 8 and 16 are on the whole topology, except for vlan 16 which is on every single interswitch link, but the VLAN itself does not exist on the remote wan switch... it does however exist on the links to it at both ends.
interface GigabitEthernet1/0/3
description RB01-LAN0_0
switchport access vlan 8
switchport mode access
speed 1000
duplex full
srr-queue bandwidth share 10 10 20 60
srr-queue bandwidth shape 10 0 0 0
priority-queue out
mls qos trust dscp
no cdp enable
spanning-tree bpduguard disable
end
gpl-1-wansw02#show run int gi1/0/4
Building configuration...
Current configuration : 312 bytes
!
interface GigabitEthernet1/0/4
description RB01-WAN0_0
switchport access vlan 16
switchport mode access
speed 1000
duplex full
srr-queue bandwidth share 10 10 20 60
srr-queue bandwidth shape 10 0 0 0
priority-queue out
mls qos trust dscp
no cdp enable
spanning-tree bpduguard disable
end
The Root of VLAN 8 is seen on wansw02 int gi1/0/3. We can see what is happenning, and correct me if I am wrong, but the bpdu for vlan 16 is being sent out of int gi1/0/4 and then being forwarded by the RB into gi1/0/3, untagged but arriving on a vlan 8 interface, so the switch thinks that there is another vlan 8 switch there and it is the root.
The plan is to put bpdu filter on each interface. I think this will fix it, btu I just dont understand, 100%, why this is happenning, I know the cause, but, why does the core think its interface is the root and why does the switch not realise what is going on evertime we enable the link between the 2 wan switches?
Happy to give any more information if needed..
Thanks
Anthony
03-11-2012 01:56 AM
Still looking at your config, but I would strongly advise against configuring bpdufilter until we have thought this through.
Looking at your original posting again, I had not picked up on how wierd it really is. The bridge MAC is the same as the root MAC, but the priorities are different and the root cost is non-zero. In fact, it supports your analysis, because 24592 would actually be a VLAN 16 priority (24576 + ext. 16).
Now, how to solve it safely ... ?
Who should actually be the root of VLAN 8? If the VLAN 16 root bridge is becoming the false root of VLAN 8, it looks like you don't have anything configured for VLAN 8. But I fear that if you did configure a root for VLAN 8, the problem would simply reverse, and the VLAN 8 root would become the false root of VLAN 16.
Interesting ...
I don't know the riverbed, but does it pass broadcasts and multicasts, and does it flood unknown unicasts? If so, we have to tread very carefully.
03-12-2012 03:14 AM
Thanks Kevin
We have not put the BPDUFILTER tune on as yet. Can you tell me why we should not? The reasoning behind doing so was that we would stop any BPDU's either going to or coming from the RiverBed.
In answer to your question, our RB support company have said that they believe that the RB does pass broadcasts and multicasts and that any unknown unicasts would go via the default gateway, however, at a layer 2 level, anything that goes in one interface will be popped out the other.
Any idea why we lose all our VLAN 8 devices everytime we enable the link between wansw01 and wansw02? I was suspecting we may be causing a loop, however, at the time of the issue (and we werent on the trail of spannign tree unfortuately otherwise I would have more information) we saw no high CPU processes. We did however have a closer correlation of received to sent BPDU's on the 2 VLANs, but not any others on the switches.
I'm hopefully getting a definitive answer from RB today on how it treats traffic.
Thanks
Anthony
03-12-2012 05:35 AM
From RiverBed:
From: employee at riverbed
Subject: RE: Riverbed Support Case
Sure, the Steelhead will forward L2 b/cast, m/cast and unicast packets. In addition it will forward any L3 UDP traffic as pass-through. TCP traffic will optimized were relevant or passed through
Kind Regards,
RiverBed
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