Subject: How to set up RSTP for HP switches 2650 which is connecting to cisco 2821

Answered Question
Nov 30th, 2009

How to set up RSTP for HP switches 2650 which is connected to cisco 2821 ? Should I change anything on cisco device ?

We have a problem sometimes with our mitel phones, if somebody plugin 2 cables into it, it creates a network loop, this why I am going to use RSTP to prevent it.

Many thanks

I have this problem too.
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Correct Answer by Giuseppe Larosa about 7 years 3 days ago

Hello Vasily,

this means that PVST+ is running on cisco module

>>  Spanning tree enabled protocol ieee

each instance follows 802.1D standard (legacy STP) that is not Rapid STP

interation with HP switches can be on vlan1 with a single instance.

If this module is central device in your topology enabling Rapid STP 802.1W or 802.1s on HP switches can be of limited help for overall convergence.

Hope to help

Giuseppe

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Giuseppe Larosa Mon, 11/30/2009 - 11:58

Hello Vasily,

if the C2821 is only acting as L3 device nothing has to be changed on it.

if the C2821 has an etherswitch module you need to care of it.

Hope to help

Giuseppe

Vasily_Kr Tue, 12/01/2009 - 02:43

I have got "16 port 10BaseT/100BaseTx  EtherSwitch on Slot 1"

NM-16ESW.

All hp switches have got 1 direct connection to the c2821.

What should I change in my configuration ?

Many thanks.

Giuseppe Larosa Tue, 12/01/2009 - 06:44

Hello Vasily,

in a multivendor scenario like yours the best option is to run MST 802.1s

start to see if the following is present in IOS help

spanning-tree mode ?

see

I'm not sure it is supported on the etherswitch module.

see

http://www.cisco.com/en/US/docs/ios/12_3t/12_3t4/feature/guide/gt1636nm.html#wp1048458

It doesn't mention STP mode commands and speaks of PVST+  (one instance per vlan).

if so no form of rapid STP is available either proprietary (Rapid PVST) either standards based (802.1s MST).

Hope to help

Giuseppe

Vasily_Kr Tue, 12/01/2009 - 09:18

I selected a check boxes on all hp switches through web interfaces with options

Configuration->Device features

Spanning tree = On

I did not change anything on cisco and run:

show spanning-tree summary

I am getting:

Root bridge for: VLAN2, VLAN3, VLAN4, VLAN7, VLAN9.
PortFast BPDU Guard is disabled
UplinkFast is disabled
BackboneFast is disabled

Name                 Blocking Listening Learning Forwarding STP Active
-------------------- -------- --------- -------- ---------- ----------
VLAN1                0        0         0        5          5        
VLAN2                0        0         0        5          5        
VLAN3                0        0         0        1          1        
VLAN4                0        0         0        6          6        
VLAN7                0        0         0        1          1        
VLAN8                0        0         0        1          1        
VLAN9                0        0         0        1          1        
VLAN101              0        0         0        1          1        
VLAN103              0        0         0        1          1        
-------------------- -------- --------- -------- ---------- ----------
             9 VLANs 0        0         0        22         22      

show spanning-tree summary brief

VLAN1
  Spanning tree enabled protocol ieee
  Root ID    Priority    32768
             Address     000d.9d7f.c280
             Cost        19
             Port        53 (FastEthernet1/12)
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

  Bridge ID  Priority    32768
             Address     001d.46dc.d75a
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec
             Aging Time 300

Interface                                   Designated
Name                 Port ID Prio Cost  Sts Cost  Bridge ID            Port ID
-------------------- ------- ---- ----- --- ----- -------------------- -------
FastEthernet1/7      128.48   128    19 FWD    19 32768 001d.46dc.d75a 128.48
FastEthernet1/8      128.49   128    19 FWD    19 32768 001d.46dc.d75a 128.49
FastEthernet1/9      128.50   128    19 FWD    19 32768 001d.46dc.d75a 128.50
FastEthernet1/10     128.51   128    19 FWD    19 32768 001d.46dc.d75a 128.51
FastEthernet1/12     128.53   128    19 FWD     0 32768 000d.9d7f.c280 128.26

...

does this mean what spanning tree is working ?

Correct Answer
Giuseppe Larosa Tue, 12/01/2009 - 13:37

Hello Vasily,

this means that PVST+ is running on cisco module

>>  Spanning tree enabled protocol ieee

each instance follows 802.1D standard (legacy STP) that is not Rapid STP

interation with HP switches can be on vlan1 with a single instance.

If this module is central device in your topology enabling Rapid STP 802.1W or 802.1s on HP switches can be of limited help for overall convergence.

Hope to help

Giuseppe

Vasily_Kr Wed, 12/02/2009 - 06:57

I have found a document on HP web site: http://ftp.hp.com/pub/networking/software/AdvTraff-Oct2005-59908853-Chap05-STP_RSTP.pdf

and it was a quotation:

"

IEEE 802.1w RSTP is designed to be compatible with IEEE 802.1D STP. Even

if all the other devices in your network are using STP, you can enable RSTP

on your switch, and even using the default configuration values, your switch

will interoperate effectively with the STP devices. If any of the switch ports

are connected to switches or bridges on your network that do not support

RSTP, RSTP can still be used on this switch. RSTP automatically detects when

the switch ports are connected to non-RSTP devices in the spanning tree and

communicates with those devices using 802.1D STP BPDU packets.

"

I enabled RSTP on HP switches. At least it should protect from the network loop.

So I am going to test it during next 2-3 days.

Vasily_Kr Wed, 12/09/2009 - 08:06

Many thanks for your help,

RSTP is working.

I think what some issues(not RSTP related) what I have sometimes with my hp switches is due to old firmware installed on ones(I am going to update it).

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