From: ccie2be (ccie2be@nyc.rr.com)
Date: Sat Apr 09 2005 - 15:19:00 GMT-3
Hi Brain,
Thanks for looking at this and getting back to me.
Actually, this is a working config although for brevity I left some things
out which probably wasn't a good idea. Are the additional commands I'm now
showing the ones you were thinking about?
In addition to R-A and R-B, there's a third router, R-C, which is also part
of bridge-group 1 that's connected to both R-A and R-B which taken as a
whole creates one big 3 router bridging loop. There's still a 4th router in
this bridge group but it's not part of the bridging loop.
I understand the STP issues but I'm still puzzled by why R-A and R-B are
treating the 2 parallel pvc's that run between them like an etherchannel?
Any idea why that is?
Thanks again.
###################################################
R-A's config:
bridge irb
interface BVI1
ip address 172.16.10.1 255.255.255.0
interface ATM3/0 <- to router B
bandwidth 1544
no ip address
no atm ilmi-keepalive
pvc 100/100
!
pvc 200/200
!
bridge-group 1
interface Serial0/0
bandwidth 1544
no ip address
encapsulation frame-relay
no fair-queue
no frame-relay inverse-arp
frame-relay lmi-type ansi
!
interface Serial0/0.1 multipoint
bandwidth 1544
frame-relay map bridge 104 broadcast
frame-relay map bridge 103 broadcast <- To router C
bridge-group 1
R-A#show span
Bridge group 1 is executing the ieee compatible Spanning Tree protocol
Bridge Identifier has priority 32768, address 0000.0cb2.520c
Configured hello time 2, max age 20, forward delay 15
Current root has priority 24586, address 000a.41c7.3180
Root port is 8 (ATM3/0), cost of root path is 666
Topology change flag not set, detected flag not set
Number of topology changes 2 last change occurred 6d22h ago
from Serial0/0.1
Times: hold 1, topology change 35, notification 2
hello 2, max age 20, forward delay 15
Timers: hello 0, topology change 0, notification 0, aging 300
Port 8 (ATM3/0) of Bridge group 1 is forwarding
Port path cost 647, Port priority 128, Port Identifier 128.8.
Designated root has priority 24586, address 000a.41c7.3180
Designated bridge has priority 32768, address 0004.9ada.b0c0
Designated port id is 128.10, designated path cost 19
Timers: message age 3, forward delay 0, hold 0
Number of transitions to forwarding state: 1
BPDU: sent 36, received 599782
R-A#show bridge
Total of 300 station blocks, 294 free
Codes: P - permanent, S - self
Bridge Group 1:
Address Action Interface Age RX count TX count
0000.0c9c.3b14 forward Serial0/0.1 0 1484 1507
0004.9ada.b0c0 forward ATM3/0 0 1057 1019
0000.0c03.4080 forward ATM3/0 0 1011 880
################ router B's config ####################
bridge irb
interface BVI1
ip address 172.16.10.6 255.255.255.0
interface ATM3/0
no ip address
no atm ilmi-keepalive
!
interface ATM3/0.1 multipoint <-- To router A
bandwidth 1544
pvc 100/100
!
bridge-group 1
!
interface ATM3/0.2 multipoint <-- to router A
bandwidth 1544
pvc 200/200
!
bridge-group 1
interface FastEthernet0/0.10 <- To router C
encapsulation isl 10
no ip redirects
bridge-group 1
R-B#show span
Bridge group 1 is executing the ieee compatible Spanning Tree protocol
Bridge Identifier has priority 32768, address 0004.9ada.b0c0
Configured hello time 2, max age 20, forward delay 15
Current root has priority 24586, address 000a.41c7.3180
Root port is 7 (FastEthernet0/0.10), cost of root path is 19
Topology change flag not set, detected flag not set
Number of topology changes 5 last change occurred 6d22h ago
from ATM3/0.2
Times: hold 1, topology change 35, notification 2
hello 2, max age 20, forward delay 15
Timers: hello 0, topology change 0, notification 0, aging 300
Port 7 (FastEthernet0/0.10) of Bridge group 1 is forwarding
Port path cost 19, Port priority 128, Port Identifier 128.7.
Designated root has priority 24586, address 000a.41c7.3180
Designated bridge has priority 24586, address 000a.41c7.3180
Designated port id is 128.8, designated path cost 0
Timers: message age 1, forward delay 0, hold 0
Number of transitions to forwarding state: 1
BPDU: sent 4, received 299872
Port 9 (ATM3/0.1) of Bridge group 1 is forwarding
Port path cost 647, Port priority 128, Port Identifier 128.9.
Designated root has priority 24586, address 000a.41c7.3180
Designated bridge has priority 32768, address 0004.9ada.b0c0
Designated port id is 128.9, designated path cost 19
Timers: message age 0, forward delay 0, hold 0
Number of transitions to forwarding state: 1
BPDU: sent 299868, received 13
Port 10 (ATM3/0.2) of Bridge group 1 is forwarding
Port path cost 647, Port priority 128, Port Identifier 128.10.
Designated root has priority 24586, address 000a.41c7.3180
Designated bridge has priority 32768, address 0004.9ada.b0c0
Designated port id is 128.10, designated path cost 19
Timers: message age 0, forward delay 0, hold 0
Number of transitions to forwarding state: 1
BPDU: sent 299870, received 13
R-B#show bridge
Total of 300 station blocks, 297 free
Codes: P - permanent, S - self
Bridge Group 1:
Address Action Interface Age RX count TX count
0000.0c9c.3b14 forward ATM3/0.1 0 808 849
0000.0c3c.4efc forward ATM3/0.1 0 1118 1195
0000.0c03.4080 forward Fa0/0.10 0 1666 1533
############# R-C's config ##################################
bridge irb
interface BVI1
ip address 172.16.10.3 255.255.255.0
interface Serial0/0
no ip address
encapsulation frame-relay
no fair-queue
no frame-relay inverse-arp
frame-relay lmi-type ansi
!
interface Serial0/0.1 multipoint <-- to router A
frame-relay map bridge 301 broadcast
bridge-group 1
interface FastEthernet0/0
no ip address
duplex auto
speed auto
!
interface FastEthernet0/0.10 <-- To router B
encapsulation isl 10
no ip redirects
bridge-group 1
bridge-group 1 path-cost 648 <-- Causing the stp blocked port
R-C#show span
Bridge group 1 is executing the ieee compatible Spanning Tree protocol
Bridge Identifier has priority 32768, address 0050.547c.99c0
Configured hello time 2, max age 20, forward delay 15
Current root has priority 24586, address 000a.41c7.3180
Root port is 11 (FastEthernet0/0.10), cost of root path is 667
Topology change flag not set, detected flag not set
Number of topology changes 2 last change occurred 02:34:46 ago
from Serial0/0.1
Times: hold 1, topology change 35, notification 2
hello 2, max age 20, forward delay 15
Timers: hello 0, topology change 0, notification 0, aging 300
Port 11 (FastEthernet0/0.10) of Bridge group 1 is forwarding
Port path cost 648, Port priority 128, Port Identifier 128.11.
Designated root has priority 24586, address 000a.41c7.3180
Designated bridge has priority 32778, address 000a.8a46.8300
Designated port id is 128.3, designated path cost 19
Timers: message age 3, forward delay 0, hold 0
Number of transitions to forwarding state: 1
BPDU: sent 2, received 90143
Port 14 (Serial0/0.1) of Bridge group 1 is blocking
Port path cost 647, Port priority 128, Port Identifier 128.14.
Designated root has priority 24586, address 000a.41c7.3180
Designated bridge has priority 32768, address 0000.0cb2.520c
Designated port id is 128.16, designated path cost 666
Timers: message age 3, forward delay 0, hold 0
Number of transitions to forwarding state: 1
BPDU: sent 210, received 174252
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Brian Dennis
Sent: Saturday, April 09, 2005 1:24 PM
To: ccie2be; Group Study
Subject: RE: multi parallel pvc's and bridging
Tim,
You need to step back and get a working configuration first.
The configuration you have doesn't work. Also once you figure out what
commands are missing, your router R-A will no allow you to enter the
commands to do what you are trying to do ;-) Play around with it and
then think about why the router will not allow this and you'll have
figured it out.
You should have been able to tell by looking at the "show span"
that the routers do not see each other which would have indicated to you
that you do not have a working configuration.
Brian Dennis, CCIE #2210 (R&S/ISP-Dial/Security
bdennis@internetworkexpert.com
Internetwork Expert, Inc.
http://www.InternetworkExpert.com
Toll Free: 877-224-8987
Direct: 775-745-6404 (Outside the US and Canada)
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
ccie2be
Sent: Saturday, April 09, 2005 9:18 AM
To: Group Study
Subject: multi parallel pvc's and bridging
Hi guys,
Look at this scenario. There are 2 pvc's going between R-A and R-B. In
this
example, they just happen to be ATM, but could just as well been f/r
pvc's.
R-A's config:
interface ATM3/0
bandwidth 1544
no ip address
no atm ilmi-keepalive
pvc 100/100
!
pvc 200/200
!
bridge-group 1
R-B's config:
interface ATM3/0.1 multipoint
bandwidth 1544
pvc 100/100
!
bridge-group 1
!
interface ATM3/0.2 multipoint
bandwidth 1544
pvc 200/200
!
bridge-group 1
I've got a couple questions about this config. Maybe someone can help me
understand this better.
First, let me confirm that although the config's for R-A and R-B are
done a
little differently, functionally they're equivalent, correct?
(If that's not true, then my real questions might not make any sense.)
OK, here's what I need to understand.
Is the above config for R-A and R-B functionally equivalent to having an
etherchannel between R-A and R-B except instead of 2 physical links,
there
are 2 logical links?
I want to make sure because otherwise there would be spanning tree
issues
and one of the pvc's will be blocked.
If these 2 pvc's are being treated like an etherchannel, why is that?
From looking at these config's, I would have thought that the routers
would
treat each pvc like a physical link and then used STP to block one of
the
pvc's, but that doesn't seem to be happening. (I did a show span and
all
pvc's were forwarding.)
If someone can explain this, I'd be very grateful.
TIA, Tim
This archive was generated by hypermail 2.1.4 : Tue May 03 2005 - 07:54:55 GMT-3