Avaya ERS4526 Trap: RSTP Topology Change

[Thuy_Vu]

Hi,

ERS4526 which is access switch, only connect end user and two links to Core Switch. Two links are always up. Switch have logs about "Trap: RSTP Topology Change" when Link Up Trap for Unit/Port.

ERS4526_#show logging sort-reverse unit 1
Type Unit Time Idx Src Message
---- ---- ----------------------------- ---- --- -------
I 1 151:18:00:28 35527 Link Up Trap for Unit/Port:
4 / 22
I 1 151:18:00:26 35526 Link Down Trap for Unit/Port
: 4 / 22
I 1 151:17:58:41 35525 Trap: RSTP Topology Change
I 1 151:17:58:11 35524 Link Up Trap for Unit/Port:
4 / 22
I 1 151:17:58:08 35523 Link Down Trap for Unit/Port
: 4 / 22
I 1 151:17:58:04 35522 Link Up Trap for Unit/Port:
4 / 22
I 1 151:17:58:01 35521 Link Down Trap for Unit/Port
: 4 / 22
I 1 151:17:57:59 35520 Link Up Trap for Unit/Port:
4 / 22
I 1 151:17:57:55 35519 Link Down Trap for Unit/Port
: 4 / 22
I 1 151:17:57:47 35518 Trap: RSTP Topology Change
I 1 151:17:57:16 35517 Link Up Trap for Unit/Port:
3 / 5
I 1 151:17:57:09 35516 Link Down Trap for Unit/Port

I try to enable edge-port and bpdu-filtering on interfaces which connect to end user (4/22, 3/5). But it still appear when Link up Trap, then Trap: RSTP Topology Change.

Question:
1. Why do "Trap: RSTP Topology Change" appear when interface up/down, although interface connect end user?
2. How to disable Trap RSTP Topology Change?

! Base model = Ethernet Routing Switch 4526GTX
! Base Software version = v5.4.0.008
Thanks,

[Vali_Ene]

From the show spanning-tree rsts port config 1/2 and 1/8 I can see that the Edge-Port is disabled on both ports (The line "Port Admin Edge Status: False"). It's absolutely normal to have Topology Change when those ports are moving from up to down or vice-versa as they are full STP enabled.
You must config the access ports as edge-ports using the following example:

4524GT>ena
4524GT#conf t
4524GT(config)#interf fast 1-10
4524GT(config-if)#spanning-tree rstp port 1-10 edge-port true
4524GT(config-if)#show spanning-tree rstp port config 1

Port: 1
----------
Port Priority (hex): 80
Port Path Cost: 20000
Port Protocol Migration: False
Port Admin Edge Status: True
Port Oper Edge Status: True
Port Admin P2P Status: Auto
Port Oper P2P Status: True
Port Oper Protocol Version: Rstp

[Vali_Ene]

If there is any chance to create a loop on those ports then let them full STP. If you don't have a too fancy topology and there is no chance that someone to create a loop using the APs uplinks then edge ports are just fine. You must keep in mind a very simple fact: enable STP only on ports that are susceptible to loops - every Topology Change sent in the switched network means a flush MAC forwarding table on every switch in your network, flooding of frames until the MAC tables are rebuild etc

[Thuy_Vu]

Hi,
What's about interface connect to Access-Point? To configure edge-port or non-edge port

Thanks,

[Vali_Ene]

• First of all verify that the STP Mode is RSTP (as I understand you need):

4524GT(config-if)#show spanning-tree rstp config
The output should be "Stp Version: Rstp Mode"

• Second, verify the operational edge status of one port:

4524GT(config-if)#show spanning-tree rstp port config 1
The output should look like this:
Port Admin Edge Status: True
Port Oper Edge Status: True

The above commands were ran on this system: sysDescr:
Ethernet Routing Switch 4524GT
HW:08 FW:5.3.0.3 SW:v5.6.2.026

Later edit: yes, the command to enable the edge ports looks right (at interface level - interf fast 1-10, enter spanning-tree rstp edge-port true)