Need help on bridging

Answered Question
Aug 29th, 2008

hi,

In my network i have some switches which is runing Bridigeing instance.. now i am planning to migrate to STP. what precaution in need to take..

connectivity..

COre-- BRIDGE SW(2948) -- PC

sample config of one VLAN in both the switches..

interface BVI64

ip address 172.16.164.3 255.255.255.0

no ip redirects

no ip directed-broadcast

standby 164 priority 100

standby 164 ip 172.16.64.1

interface Vlan164

ip address 172.16.64.2 255.255.254.0

no ip redirects

no ip unreachables

no ip proxy-arp

ip route-cache flow

standby 164 ip 172.16.164.1

standby 164 priority 200

standby 164 preempt

For two they have given two GW for one VLAN..

pls help me out

Regards

sateesh kumar.k

I have this problem too.
0 votes
Correct Answer by Giuseppe Larosa about 8 years 3 months ago

Hello Sateesh,

everything is ok

be aware that this switch could be unable to support L3 Vlan this depends on the IOS code on it.

You may need to upgrade it to use the Vlan Syntax and to take advantage of real PVST+.

Hope to help

Giuseppe

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Giuseppe Larosa Fri, 08/29/2008 - 11:53

Hello Sateesh,

BVI are used by IRB = Integrated Routing and Brdiging

you can equate one BVI as one L3 Vlan like Vlan164.

all ports with bridge-group 64 are part of the same L2 VLan broadcast domain

be aware that STP is already running on IRB may be with a standard 802.1D CST version

if you do show spanning-tree on the switches using the BVI you can see it

Hope to help

Giuseppe

sateeshk10 Fri, 08/29/2008 - 12:01

pls find below sh span-tree from BVI..pls chk an d confirm

if so what to do...???

sw#sh spanning-tree

Bridge group 132 is executing the IEEE compatible Spanning Tree protocol

Bridge Identifier has priority 32768, address 0003.9f17.a807

Configured hello time 2, max age 20, forward delay 15

Current root has priority 8192, address 0009.b7ad.e083

Root port is 63 (GigabitEthernet50.132), cost of root path is 4

Topology change flag not set, detected flag not set

Times: hold 1, topology change 35, notification 2

hello 2, max age 20, forward delay 15

Timers: hello 0, topology change 0, notification 0

bridge aging time 300

Port 4 (FastEthernet1) of Bridge group 132 is down

Port path cost 19, Port priority 128

Designated root has priority 8192, address 0009.b7ad.e083

Designated bridge has priority 32768, address 0003.9f17.a807

Designated port is 4, path cost 4

Timers: message age 0, forward delay 0, hold 0

BPDU: sent 0, received 0

Giuseppe Larosa Fri, 08/29/2008 - 12:57

Hello Sateesk,

just check that the root bridge ID is that of your core switch

Current root has priority 8192, address 0009.b7ad.e083

on interfaces the core switch should revert to IEEE 802.1D instead of using PVST+.

Bridge group 132 is executing the IEEE compatible Spanning Tree protocol

Bridge Identifier has priority 32768, address 0003.9f17.a807

Configured hello time 2, max age 20, forward delay 15

>> Current root has priority 8192, address 0009.b7ad.e083

Root port is 63 (GigabitEthernet50.132), cost of root path is 4

Topology change flag not set, detected flag not set

Times: hold 1, topology change 35, notification 2

hello 2, max age 20, forward delay 15

Timers: hello 0, topology change 0, notification 0

bridge aging time 300

If the core switch is the root bridge and is using 802.1D on the port to the switch using BVIs everything should be fine

Hope to help

Giuseppe

sateeshk10 Fri, 08/29/2008 - 13:05

Hi,

pls find below the my core sw spantree..bUT MAC ADD DIFFRENT..PLS CHK

COreSW#sh spanning-tree

VLAN1 is executing the ieee compatible Spanning Tree protocol

Bridge Identifier has priority 8192, address 0009.b7ad.e000

Configured hello time 2, max age 20, forward delay 15

We are the root of the spanning tree

Topology change flag not set, detected flag not set

thanks

sateesh

Giuseppe Larosa Fri, 08/29/2008 - 13:20

Hello Sateesh,

address 0009.b7ad.e083

0009.b7ad.e000

vlan 132 without MAC address reduction means a different mac address for each vlan instance.

do a show spanning-tree vlan x on core switch

where x is the vlan that pairs with Bridge-group 132

It should be fine a good news is: "ieee compatible Spanning Tree protocol"

Hope to help

Giuseppe

sateeshk10 Fri, 08/29/2008 - 13:23

Hi ,

your are right..pls find below the same..

pls let me know shall i enable STP on my sw

crsw#sh spanning-tree vlan 132

VLAN132 is executing the ieee compatible Spanning Tree protocol

Bridge Identifier has priority 8192, address 0009.b7ad.e083

Configured hello time 2, max age 20, forward delay 15

Regards

sateesh

sateeshk10 Fri, 08/29/2008 - 13:31

And also my plan that...i will take out this sw from network and reconfigure for STP and i put back into the network...

is it ok..

Regards

sateesh kumar.k

Correct Answer
Giuseppe Larosa Sat, 08/30/2008 - 09:23

Hello Sateesh,

everything is ok

be aware that this switch could be unable to support L3 Vlan this depends on the IOS code on it.

You may need to upgrade it to use the Vlan Syntax and to take advantage of real PVST+.

Hope to help

Giuseppe

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