[c-nsp] Hardware accel. paths for policy routing on C6500

[Tim Stevenson]

As long as you match on DSCP using an ACL, it is in hardware. ie:

access-list 101 permit ip any any dscp cs5

or similar.

Tim

At 08:56 AM 2/15/2005, Sam Stickland averred:
>Is matching against dscp values also in done in software?
>
>Sam
>
>On Tue, 15 Feb 2005, Tim Stevenson wrote:
>
>>Correct, match ip community will force software switching.
>>
>>We support match ip address, set ip next-hop, set ip default next-hop, 
>>and set interface null0 in hardware - anything else is in software.
>>
>>Tim
>>
>>At 06:44 AM 2/15/2005, Sam Stickland averred:
>>>On Tue, 25 Jan 2005, Per Carlson wrote:
>>> > Sam Stickland wrote:
>>> >> Measuring traffic from the customer to our peers is easy (simply 
>>> provision
>>> >> another BGP session only containing peer route). Traffic from our 
>>> peers to
>>> >> our customers is more difficult. Since there'd be two possible paths 
>>> from
>>> >> our network to the customers (full and partial), we'd need to route 
>>> based
>>> >> on the source address as well as the destination.
>>> >>
>>> >> My thinking is to dscp mark the traffic from our directly connected 
>>> peers
>>> >> (at the same point where we apply community tags), and then policy 
>>> route on
>>> >> the customers directly attached interface.
>>> >
>>> > afaik, policy routing is enabled on the *ingress* interface. from the 
>>> cisco
>>> > config guide (http://tinyurl.com/2o5m7 [1])
>>>Oh, of course you're right. Well that makes this a litte bit trickier
>>>doesn't it?
>>> > you would need to create route-maps matching the customer prefixes 
>>> with the
>>> > right next-hop, like
>>> >
>>> > route-map partitial permit 10
>>> >  match ip address cust1_prefixes
>>> >  set ip next-hop 1.1.1.1
>>> > route-map partitial permit 20
>>> >  match ip address cust2_prefixes
>>> >  set ip next-hop 2.2.2.2
>>>Wouldn't this need to be:
>>>route-map partitial permit 10
>>>     match ip community 10
>>>     match ip address cust1_prefixes
>>>     set ip next-hop 1.1.1.1
>>>route-map partitial permit 20
>>>     match ip community 10
>>>     match ip address cust2_prefixes
>>>     set ip next-hop 2.2.2.2
>>>Since we won't to not only match where the traffic is going, but also
>>>where it is from (ie. direct traffic from directly connected peers to a
>>>different next-hop). It would be nice if we could match this via
>>>community, but once again I fear that this information isn't going to be
>>>available at this point in the hardware?
>>>Sam
>>> > this doesn't scale well, you would need to maintain separate acl's 
>>> for each
>>> > customer with all their prefixes. sure it would be maintainable with a
>>> > handful of customers with a handful of prefixes each.
>>> >
>>> > i've been looking into this as well, but more or less given up the pbr
>>> > track.
>>> >
>>> > i'd love if you could do it the following way:
>>> >
>>> > route-map partitial permit 10
>>> >  match ip destination as-path 1
>>> >  set ip next-hop 1.1.1.1
>>> >
>>> > ip as-path access-list 1 permit 1234
>>> >
>>> > this approach would be rather hard to do in hardware tough :-( if the
>>> > cef-table did have information about the as number, it might be 
>>> possible...
>>> >
>>> > per
>>> >
>>> > [1]
>>> > 
>>> http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122cgcr/fipr_c/ipcprt2/1cfindep.htm#wp1001398
>>> >
>>> >
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>>
>>
>>
>>Tim Stevenson, tstevens at cisco.com
>>Routing & Switching CCIE #5561
>>Technical Marketing Engineer, Catalyst 6500
>>Cisco Systems, http://www.cisco.com
>>IP Phone: 408-526-6759
>>********************************************************
>>The contents of this message may be *Cisco Confidential*
>>and are intended for the specified recipients only.



Tim Stevenson, tstevens at cisco.com
Routing & Switching CCIE #5561
Technical Marketing Engineer, Catalyst 6500
Cisco Systems, http://www.cisco.com
IP Phone: 408-526-6759
********************************************************
The contents of this message may be *Cisco Confidential*
and are intended for the specified recipients only.