11-19-2012 11:28 PM - edited 03-07-2019 10:08 AM
Hi,
I am currently having performance issues running a 3 x stack 3750G (different models) as a core for a network of roughly 12 x distribution switches.
Switch Ports Model SW Version SW Image
------ ----- ----- ---------- ----------
* 1 12 WS-C3750G-12S 12.2(50)SE5 C3750-IPBASE-M
2 52 WS-C3750G-48PS 12.2(50)SE5 C3750-IPBASE-M
3 52 WS-C3750G-48PS 12.2(50)SE5 C3750-IPBASE-M
As above, I have a 12 port Fibre switch and 2 x 3750G-48 port switches.
I received this error:
%PLATFORM_UCAST-6-PREFIX: One or more, more specific prefixes could not be programmed into TCAM and are being covered by a less specific prefix
Isuues are:
-high latency and spikes when trying to ping internal servers
-High CPU Utilization, average of ~45-50%
-Very slow performance overall
I believe the slow performance is due to the SDM Template. The SDM Template i am currently running is: desktop VLAN, which was on by default.
The current template is "desktop vlan" template.
The selected template optimizes the resources in
the switch to support this level of features for
8 routed interfaces and 1024 VLANs.
number of unicast mac addresses: 12K
number of IPv4 IGMP groups + multicast routes: 1K
number of IPv4 unicast routes: 0
number of IPv4 policy based routing aces: 0
number of IPv4/MAC qos aces: 0.5K
number of IPv4/MAC security aces: 1K
I tried to change the SDM to route but hit another issue where the 3750g-48 does not support SDM route so I had to revert back to desktop VLAN.
Could the SDM Template be the reason for slow performance? If so which SDM Template should i use as this is the Core L3 switch.
Solved! Go to Solution.
11-20-2012 10:44 AM
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Posting
Try either "sdm prefer default desktop" or "sdm prefer routing desktop", and if accepted, then reload.
11-20-2012 02:35 AM
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The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.
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In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.
Posting
3750G models do support a routing SDM template, but the -12S supports SDM templates unique to it. I recall in a mixed stack of 12S and other 3750 models, you shouldn't use 12S SDM templates. So, I'm wondering whether you were, perhaps, invoking a 12S routing SDM template. What are all your SDM template options?
PS:
And yes, if you overflow TCAM resources, a 3750's performance will generally very much degrade.
11-20-2012 03:51 AM
Hi,
Thanks for your respone, from memory the options for SDM were:
SDM prefer Access/Vlan/Routing/Default
Not too sure what the desktop command does but its an option after selecting one of the four options, for e.g;
(config)# SDM prefer default desktop
OR
(config)# SDM prefer default
^Found out the answer to the desktop command, see below;
There are two versions of each template: a desktop template and an aggregator template. The Catalyst 3750-12S switch can use the larger TCAM size available in the aggregator templates or can use the standard desktop templates. All other Catalyst 3750 switches support only the desktop templates. If you do not enter the desktop keyword on an aggregator switch, the aggregator templates are selected.
Source:
11-20-2012 10:44 AM
Disclaimer
The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.
Liability Disclaimer
In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.
Posting
Try either "sdm prefer default desktop" or "sdm prefer routing desktop", and if accepted, then reload.
11-21-2012 12:12 AM
Problem resolved today, issued "sdm prefer default desktop" and everything is running smoothly.
Thanks
11-21-2012 02:32 AM
Disclaimer
The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.
Liability Disclaimer
In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.
Posting
Great! In that case, you might want to mark this issue as correctly answered, so others may know it might be used if they have a similar problem.
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