MPLS layer 2 connection

[olly ahmed]

Hi I want assitance regarding the below issues:

Layer 2 network has susciptibility to broadcast strom. And my question is, does MPLS layer 2 vpn connection has same problem of broadcast strom ? I mean that if any broadcast issues happen from a MPLS layer 2 vpn client will it affect my core network (MPLS core backbone) ?

[Vinit Jain]

The broadcast storm may not affect your MPLS Core but can possibly affect the PE router itself. We have seen instances in VPLS deployment where high CPU has been noticed. For example, if the PE router is a Cisco 7600 series platform, then you can see SP (Switch Processor) CPU spike up.

Hope this answers your question.

Regards

Vinit

[olly ahmed]

Hi Jain, thanks for your answer as I got it helpful. Could you just explain how and why it will not affect the mpls core ?

[Vinit Jain]

All the packets coming form the CE devices are encapsulated into MPLS packet. Thus in the core, what we see is just an MPLS packet and the packets will just perform mpls lookup and forward the packet. the packet doesnt really needs to get punted to the Route Processor (RP) for further lookup and thus will not cause an impact on the CPU.

Its only the edge (PE) or the CE devices which see the impact of a broadcast strom in a l2vpn scenario.

If the broadcast storm is internal to the provider network itself, then the core devices may have some impact but not otherwise.

Hope this clarifies.

Regards

Vinit

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[olly ahmed]

Can you elaborate the issue as you said "If the broadcast storm is internal to the provider network itself, then the core devices may have some impact but not otherwise".