Re: cam timer tuning

Thanks for responding Joe. here is a brief summary of topology

Pair of nexus
7k (csw01/csw02) in core, set of access switches (asw's) connected to both of
them.eg asw324 t1/49 connected to csw01 and t1/50 connected to csw02. no
port-channelling. csw01 is HSRP primary and STP root for all the vlans. MSTP
running in the environment. looking at asw, t1/49 is root port and t1/50 is
blocking port. below is the config on asw's. whenever we add any new asw, we
see the flooding for more than 10 minutes until arp is cleared.

interface
TenGigabitEthernet1/49
 description eat1-22164-csw01-eth2-9.corp
 switchport
trunk allowed vlan 790
 switchport mode trunk
 switchport nonegotiate
 mtu
9198
 logging event link-status
 logging event trunk-status
 udld port
aggressive
 spanning-tree portfast disable
 spanning-tree bpduguard disable
 spanning-tree link-type point-to-point
end

interface TenGigabitEthernet1/50
 description eat1-22164-csw02-eth2-9.corp
 switchport trunk allowed vlan 790
 switchport mode trunk
 switchport nonegotiate
 mtu 9198
 logging event
link-status
 logging event trunk-status
 udld port aggressive
 spanning-tree
portfast disable
 spanning-tree bpduguard disable
 spanning-tree link-type
point-to-point
end

eat1-22164-asw324.corp#sh spanning-tree vlan 790

MST1
 
Spanning tree enabled protocol mstp
  Root ID Priority 8193
           
 Address 4055.3909.5a41
             Cost 2000
             Port
     49 (TenGigabitEthernet1/49)
             Hello Time 2 sec Max Age 20
sec Forward Delay 15 sec

  Bridge ID Priority 61441 (priority 61440
sys-id-ext 1)
             Address 2c54.2dbd.13c0
             Hello Time
  2 sec Max Age 20 sec Forward Delay 15 sec

Interface Role Sts
Cost Prio.Nbr Type
------------------- ---- --- --------- --------
--------------------------------
Te1/49 Root FWD 2000 128.49
  P2p
Te1/50 Altn BLK 2000 128.50 P2p

CSW config
interface Ethernet2/9
  description eat1-22164-asw324-te1-50.corp
  switchport
  switchport mode trunk
  switchport trunk allowed vlan 790
  spanning-tree
link-type point-to-point
  spanning-tree guard root
  mtu 9216
  logging event
port link-status
  logging event port trunk-status
  udld aggressive
  no
shutdown

________________________________
 From: Joe Sanchez
<marco207p_at_gmail.com>
To: Naufal Jamal <naufalccie_at_yahoo.in>
Cc: Carlos G
Mendioroz <tron_at_huapi.ba.ar>; "ccielab_at_groupstudy.com"
<ccielab_at_groupstudy.com>
Sent: Friday, 28 December 2012 10:21 PM
Subject: Re:
cam timer tuning
 

Naufal,

you say your using Nexus without vPC... connected
to 4948's , can you give us more information as to how you have the nexus and
4948's connected and what configuration they on them. Trying to solve for a
an issue with this little of information is difficult.

JS.

On Fri, Dec 28,
2012 at 10:42 AM, Naufal Jamal <naufalccie_at_yahoo.in> wrote:

Carlos- unicast
flooding due to TCN is understood by design but does it really
>go on for 10
minutes?? our network graphs shows spikes for nearly 10 minutes
>until we do a
clear ip arp. This really should not be happening in a stable
>STP
environment.. Anyways i am trying the below URL
>http://www.cisco.com/en/US/products/hw/switches/ps708/products_tech_note09186
>a00807347ab.shtml#broadcast
>
>
>
>
>________________________________
> From:
Carlos
>G Mendioroz <tron_at_huapi.ba.ar>
>To: Naufal Jamal <naufalccie_at_yahoo.in>
>Cc:
>"ccielab_at_groupstudy.com" <ccielab_at_groupstudy.com>
>Sent: Friday, 28
December
>2012 3:41 PM
>Subject: Re: cam timer tuning
>
>
>What makes you
believe that the
>difference has anything to do with it ?
>Specially after
(correctly) infering
>that TC is causing the flooding!
>
>TC means a MAC could
be now anywhere else
>(from a switch standpoint) so
>I guess the solution to
your problem (flooding)
>is to get rid of STP :)
>
>-Carlos
>
>Naufal Jamal @
28/12/2012 06:40 -0300 dixit:
>> Hello,
>>
>> We have a pair of nexus 7K's
(without vpc) running HSRP and MSTP.
>> They are connected to access layer
switches 4948's. whenever we bring up a
>new
>> trunk link between Nexus 7K
and 4948 we see unicast flooding caused due
>to
>> TCN's. I am wondering if it
has something to do with the difference in
>cam
>> aging timer in both the
platforms. Nexus (1800 secs) and 4948 (300
>secs). can
>> anyone put some
light here please? I am thinking that changing
>the aging timer
>> on nexus to
300 secs should help.. any thoughts?
>>
>> Naufal
>>
>>
>> Blogs and organic
groups at http://www.ccie.net
>>
>>
>_______________________________________________________________________
>>
>Subscription information may be found at:
>>
>http://www.groupstudy.com/list/CCIELab.html
>>
>>
>>
>>
>>
>>
>>
>
>--
>Carlos G
>Mendioroz <tron_at_huapi.ba.ar> LW7 EQI Argentina
>
>
>Blogs and
organic groups
>at http://www.ccie.net
>_______________________________________________________________________
>Subscription information may be found at:
>http://www.groupstudy.com/list/CCIELab.html
>
>
>Blogs and organic groups at
http://www.ccie.net
>
>_______________________________________________________________________
>Subscription information may be found at:
>http://www.groupstudy.com/list/CCIELab.html

Blogs and organic groups at http://www.ccie.net
Received on Sat Dec 29 2012 - 01:01:22 ART