point to point (p2p) switching

[Amirmahdi.M]

Hi Everyone

My question might seem dumb but is there a way for a cisco 4500x to switch traffic between 2 interfaces (trunk or access) without MAC learning?

I mean like ASR routers that have VPWS(xconnect) running and only know left and right without any MAC learning.

Thanks

Amir

[MHM Cisco World · Accepted solution]

It by defualt bridge two interface'

But different when SW learn MAC and SW dont learn MAC is the 

Unknown unicast flood 

When SW learn mac it forward to specific port depend one mac table 

When SW NOT learn mac it flood to all port in that vlan' this called unknown unicast.

MHM

[Amirmahdi.M]

Hi @MHM Cisco World 

I dont want the traffic to flood on all ports.

This is what i had in mind:

If the traffic comes from Te1/1(Left) then forward it to Te1/2(right)

If the traffic comes from Te1/2(right) then forward it to Te1/1(Left)

p2p forwarding

without any mac learning.

thanks

Amir

[MHM Cisco World · Accepted solution]

Put both port in one vlan and SW will flood traffic between two ports.

The different between flood and forward' forward use tcan and flood use some addiotonal SW resource.

Note:- by defualt sw read l2 header and learn mac for any ingress traffic 

MHM 

[Amirmahdi.M]

Hello again @MHM Cisco World 

Lets assume i have a 4500x32 and 2 Te Ports in one vlan.

Can we estimate how much additional resource (compared to normal) will it use to switch 8Gbps of traffic from one interface to another?

Thanks

Amir

[Amirmahdi.M]

I wanted to disable mac learning to save resource   (AFAIK the switch can learn upto 55k MACs but each of our users have about 5-10k MAC addresses)

I needed something like a Router's L2vpn but on a switch. I dont think its possible.

Thanks for your help

Amir

[MHM Cisco World]

55K MAC' are sure this max MAC can this SW save?

User have many MAC is it VM user ?

Thanks 

MHM

[Amirmahdi.M]

Hi

55k is the maximum number of MAC addresses 4500x can handle.

https://www.cisco.com/c/en/us/products/collateral/switches/catalyst-4500-x-series-switches/data_sheet_c78-696791.html

The user is a local ISP and it's users's PPPoE traffic is going to pass through the switch.

I dont know the number of users but if we give this kind of service to a few more ISPs, we will surely face a problem with the switch.

I really wanted to replace the switch with an asr903 but its not possible at the moment.

Can we estimate how much additional resource the Unkown Unicast Flood will use for about 8 Gbps? (Vlan only having 2 Ports)

Thanks

Amir

[MHM Cisco World]

MHM

[MHM Cisco World]

You want to replace asr900 BNG with c4500.

Hmm' that tricky Q' I will check.

For Mac the ASR see few mac address and PPPoE use session ID instead of Mac to forward traffic.