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What is the difference between local-proxy-arp and arp suppression in EVPN network?

2020-10-19 Published

Problem Description

What is the difference between  local-proxy-arp and arp suppression? What are the application scenarios of the two?

Solution

Local-proxy-arp and arp suppression refer to different forwarding modes in EVPN VXLAN distributed gateway network.

Local-proxy-arp mode: forwarding between hosts in the same subnet is carried out by matching MAC table.

Arp suppression mode: forwarding between hosts in the same subnet is carried out by matching host routes. 

Advantages of  local-proxy-arp mode: each leaf can only save local MAC table and ARP table, and allocate most of the hardware resources to routing table, which can enable the whole network to support more host to access.

Disadvantages of local-proxy-arp mode: it can not support some L2 applications, such as non IP packets and layer 2 messages with TTL equal to 1.