VRRP
- Advantages of using VRRP:
- If one router goes down, we don’t need to manually configure in the many devices downstream. We use the virtual IP as the gateway on the devices.
- Process:
- We give a ID on the routers which we want to be part of VRRP. If we have the same ID on the routers, then, they both create a virtual Mac. (the SRC mac is a new Mac and dest mac is a well-known mac. Also, the destination IP is a well-known multicast IP (224.0.0.18)
- Then, depending on the priority, physical IP on the routers, the Master and Backup router is determined. The router which has higher priority will win the election (In Arista, the default priority is 100)
- Note:
- The routers are expensive.
- Also, the probability of a complete router going down is less as compared to a link going down
- So, to use resources effectively, use a different router for different vlan
- Also, VRRP is interface specific
- Reelection Process:
- If the election process is completed and then, the master router goes down, the Backup becomes the new master.
- Now, if the master comes back up again, will re-election happen?
- Other than the VRRP control packets, for any data that is being sent to outside network, the packet rewriting at the current Master Router uses the physical Mac address of that router.
- http://www.programering.com/a/MDM2IzNwATc.html