[c-nsp] Routing performance of ME3400

[Eric Van Tol]

Hello,
Check your SDM template - you probably have it set to 'layer-2' when it should be 'default' for layer 3 routing.

switch#sh sdm prefer 
 The current template is "default" 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:                  5K
  number of IPv4 IGMP groups + multicast routes:    1K
  number of IPv4 unicast routes:                    9K
    number of directly-connected IPv4 hosts:        5K
    number of indirect IPv4 routes:                 4K
  number of IPv4 policy based routing aces:         0.5K
  number of IPv4/MAC qos aces:                      0.5K
  number of IPv4/MAC security aces:                 1K


-evt

> -----Original Message-----
> From: cisco-nsp-bounces at puck.nether.net [mailto:cisco-nsp-
> bounces at puck.nether.net] On Behalf Of Garry
> Sent: Wednesday, October 27, 2010 10:18 AM
> To: cisco-nsp at puck.nether.net
> Subject: [c-nsp] Routing performance of ME3400
> 
> Hi,
> 
> I'm trying to pinpoint a problem with a customer site ... it's hooked up
> via dual 1G SM to a central 4500. There are multiple VLANs connected.
> 
> Weird thing is this:
> 
> VLAN 999 is distributed on L2 between three sites - the customer, the
> site with the 4500, and the backbone site. All three boxes have L3
> addresses in that VLAN.
> VLAN 1999 is used only at the customer site, with its own IP subnet.
> 
> The backbone site has additional VLANs, one of which has a Linux server.
> 
> When I hook up a PC to the customer site switch, using VLAN 999 and
> another IP out of the VLAN, doing an iperf run results in "appropriate"
> throughput in either direction (server only has 100M, so the 95-98mbit
> iperf reports should be OK). In this setup, the ME3400 only does L2 with
> the packets.
> 
> Doing the same using VLAN 1999, with an IP out of that IP range, and the
> ME3400 doing L3 forwarding, incoming (towards the customer site) traffic
> throughput drops to something like 30-50Mbit, while outgoing throughput
> results in a constant (!) 16777 kbit. Remember, this is still on a 2GB
> PortChannel in uplink!
> 
> Even worse, on bidirectional traffic (incoming 30mbit e.g.), output even
> drops further, as if there were some Halfduplex issue (which there
> isn't, at least not on any interface involved, checked everything
> multiple times).
> 
> Could it be that the ME3400, albeit having the "largest" IOS on it
> (metro-ipacess) for BGP etc., is severely limited as far as L3
> performance goes? Also, I'm sporadically seeing this error:
> 
> *Mar  1 00:41:15.366: %PLATFORM_UCAST-4-PREFIX:  One or more, more
> specific prefixes could not be programmed into TCAM and are being
> covered by a less specific prefix, and the packets may be software forwarded
> 
> I did a "show platform ip unicast failed route" and got this output:
> 
> Entries covered by Actual default route(0.0.0.0/0)
>                   240.0.0.0/4 Tbl:0 : Cover:0.0.0.0/0 Tbl:0
>                   0.0.0.0/8 Tbl:0 : Cover:0.0.0.0/0 Tbl:0
>                   127.0.0.0/8 Tbl:0 : Cover:0.0.0.0/0 Tbl:0
>                   x.x.y.0/24 Tbl:0 : Cover:0.0.0.0/0 Tbl:0
>                   x.x.x.y/29 Tbl:0 : Cover:0.0.0.0/0 Tbl:0
>         Total of 5 entries covered by 0.0.0.0/0 Tbl:0
> Entries covered by Actual default route(0.0.0.0/0)
>                   240.0.0.0/4 Tbl:1 : Cover:0.0.0.0/0 Tbl:1
>                   0.0.0.0/8 Tbl:1 : Cover:0.0.0.0/0 Tbl:1
>                   127.0.0.0/8 Tbl:1 : Cover:0.0.0.0/0 Tbl:1
>         Total of 3 entries covered by 0.0.0.0/0 Tbl:1
> Entries covered by Actual default route(0.0.0.0/0)
>                   240.0.0.0/4 Tbl:2 : Cover:0.0.0.0/0 Tbl:2
>                   0.0.0.0/8 Tbl:2 : Cover:0.0.0.0/0 Tbl:2
>                   127.0.0.0/8 Tbl:2 : Cover:0.0.0.0/0 Tbl:2
>                   10.10.0.0/16 Tbl:2 : Cover:0.0.0.0/0 Tbl:2
>         Total of 4 entries covered by 0.0.0.0/0 Tbl:2
> 
> Checking Cisco's docs, the "recommended action" isn't really useful:
> 
> Quote: "Recommended Action    No action is required. "
> 
> Great. So seeing that CPU might be used for L3 forwarding does not
> warrant any action? Seeing that 0/8 route there has me somewhat worried,
> but what might cause the performance hit is the other two network routes
> listed as being covered by 0/0 ... any comments on this? Can I avoid it
> somehow? Anyway, the customer site at the moment does not report this
> error, but performance is still bad, so I reckon it's not necessarily
> caused by this ...
> 
> Hints appreciated!
> 
> Tnx, Garry
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