intervlan routing and policy routing C3750 or C 4948

Hi,

I'm testing before I buy it cisco 3750G.(i'm thinking about 4948 to )

I want use this switch as L3 router for my network.

I want to keep intervlan routing on the switch (about 50 vlans with L3
routing) and for some vlans i need different gateways.

I tried to run policy routing on incoming vlan

interface Vlan10
ip address 10.10.10.1 255.255.255.128
ip policy route-map test

interface Vlan11
ip address 10.10.10.129 255.255.255.128


interface Vlan100
ip address 200.200.200.1 255.255.255.252


access-list 1300 permit 10.10.10.0 0.0.0.127
route-map test permit 1300
match ip address 1300
set ip next-hop 200.200.200.2


in this scenerio all packets from vlan 10 are policy routed to
200.200.200.2. even traffic to vlan11.

I want policy routing for packets that aren't in local routing table.

I found on newsgroups
"
If you use "set ip next-hop" or "set interface," the precedence is: 1)
route-map, 2) routing table. So if the interface specified in the
route-map is up, or if the next-hop specified in the route-map appears
in the routing table, then the packets will be routed according to the
route-map set statement. If, on the other hand the next-hop is not in
the routing table/interface is down, then the policy will be ignored and
the packet will be routed according to the routing table (standard IOS
routing).
If you instead use "set ip default next-hop" or "set default interface,"
the behavior is exact opposite. In this case, the precedence is: 1)
routing table, 2) route-map. So if the destination matches anything in
the routing table (including a default route), the route-map will never
be used. If there is no match in the routing table for the dest IP,
then the route-map will be used to forward the packet (assuming the
specified next-hop appears in the routing table/specified interface is up).
"

but set ip default next-hop isn't CEF or Fastswitching operation for
3750G or 4948

for C 4500 ( I Think it will applay to 4948 - which is based on C4500)
I found this:


The Catalyst 4500 switching engine supports matching a "set next-hop"
route-map action with a packet on a permit ACL. All other route-map
actions, as well as matches of deny ACLs, are supported by a flow
switching model. In this model, the first packet on a flow that matches
a route-map will be delivered to the software for forwarding. Software
determines the correct destination for the packet and installs an entry
into the TCAM so that future packets on that flow are switched in
hardware. The Catalyst 4500 switching engine supports a maximum of 4096
flows


for C 3750 I found this:

IP PBR can now be fast-switched. Prior to Cisco IOS Release 12.0, PBR
could only be process-switched, which meant that on most platforms the
switching rate was approximately 1000 to 10,000 packets per second. This
speed was not fast enough for many applications. Users who need PBR to
occur at faster speeds can now implement PBR without slowing down the
router.

Fast-switched PBR supports all of the match commands and most of the set
commands, with the following restrictions:

* The set ip default next-hop and set default interface commands are
not supported.
* The set interface command is supported only over point-to-point
links, unless a route-cache entry exists using the same interface
specified in the set interface command in the route map. Also, at the
process level, the routing table is consulted to determine if the
interface is on a reasonable path to the destination. During fast
switching, the software does not make this check. Instead, if the packet
matches, the software blindly forwards the packet to the specified
interface.



-------------

There is posibility to use intervlan routing and pbr for vlans to route
outside local routing table via separate gateways (no default gateway)
and do it in hardware ?

Switch C3750G or C4948.

Thanks a lot for any good informations

siedar

 

You may tray to play with ip vrf.

 

I tried to run policy routing on incoming vlan

I may be old fashioned however policy routing is
in my view a band aid. I would be reluctant to
consider it for a new design. Make that /very/
reluctant. If someone is telling you that
they must have the facility provided by it
why not save a lot of trouble and
get that new job now

- The 4500 sounds reasonably promising.

It is not clear from this if they are talking about
hardware or software based switching. This is deliberate
on Cisco's part in the hope that you will buy it anyway.
Fastswitching is DEFINATELY software so it
would seem that in this case CEF is software
which is unlikely to be any use to you.

Neither fast /nor/ process switching use hardware based
IP routing. The performance will be terrible.


Avoid PBR - Just don't do it.

If you /must/ do it get your supplier to state
in writing that the forwarding rate for PBR is xxxMpps
where xxx is whatever is in the brochure for your
chosen model. Get ready to sue.

Finally I suspect that you will find that not
many beta testers -oops- ^h^h... customers
use PBR and so you will need to be on the look
out for gremlins.

/* Rant off */

Have fun. - Sorry Vincent but I like that too.

 

Tomasz Paszkowski napisa³(a):

How it works ? Are you use it ?