[c-nsp] SDM templates

Tóth András diosbejgli at gmail.com
Thu Oct 28 17:22:28 EDT 2010


Hi,

1) If all TCAM resources are allocated for a particular feature,
further entries will be stored in software, therefore packets hitting
those entries will be processed in software (IOW punted to CPU). SDM
templates are just repartitioning the TCAM space to be divided in
another way among different entries.

2) No, it does not. You can safely configure 128 routed interfaces
without any problem. Note that the more SVIs you configure, the more
processor memory you will use. Also, the CPU utilization might
increase with an increasing number of SVIs. While the total maximum of
supported SVI is 1000, keep in mind that the maximum number of STP
instances is 128 with PVST+ and Rapid-PVST+.

Quote from the 3750 Data Sheet:
128 switch virtual interfaces (SVIs) are recommended. Maximum of 1000
are supported (depending on the number of routes and multicast
entries). 468 routed ports are supported per stack.
http://www.cisco.com/en/US/prod/collateral/switches/ps5718/ps5023/product_data_sheet0900aecd80371991.html

3) Routed interface includes L3 (no switchport) ports and SVIs as well.

If you want to read more details, refer to Understanding and
Configuring Switching Database Manager on Catalyst 3750 Series
Switches guide on the following link:
http://www.cisco.com/en/US/products/hw/switches/ps5023/products_tech_note09186a00801e7bb9.shtml

Cheers,
Andras


On Thu, Oct 28, 2010 at 10:57 PM, Bill Blackford
<BBlackford at nwresd.k12.or.us> wrote:
> Ok, stupid questions about SDM.
>
> When I issue a 'sh sdm prefer' I see that my 3560 is using the "desktop default" template. When I issue 'sh sdm prefer routing' I see that I get less MACs and more IPV4 routes. This all begs the questions:
>
> 1. Is this showing me what resources are allocated to the TCAM (IOW, in hardware) and anything exceeding is punted to the CPU?
>
> 2. In both cases above, I'm shown that "This template optimizes the resources in the switch to support this level of features for 8 routed interfaces and 1024 VLANs." Does this mean that the 9th routed interface is punted to the CPU as well?
>
> 3. Does "routed interfaces" mean just that or is it also referring to SVI's?
>
>
> Thanks,
>
> -b
>
>
> --
> Bill Blackford
> Senior Network Engineer
> Technology Systems Group
> Northwest Regional ESD
>
> Logged into reality and abusing my sudo priviledges
>
>
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