Virtual MAC (VMAC) considerations on SLX devices affect the number of VRRP virtual router IDs (VRIDs) available for the VRRP and VRRP Extended (VRRP-E) sessions.
When you configure a virtual routing ID (VRID), the software automatically uses the MAC address as the MAC address of the virtual router. The first five octets of the address are the standard MAC prefix for VRRP packets. The last octet is the VRID.
When the virtual router becomes the master router, it broadcasts a gratuitous ARP (GARP) request containing the virtual router‘s MAC address for each IP address associated with the virtual router. Hosts use the MAC address of the virtual router in routed traffic they send to their default IP gateway.
You can manually configure a unique virtual MAC address for each IPv4 and IPv6 VRRP instance per VRID. If there is no manually configured virtual MAC address for a VRRP instance, the system automatically assigns one.
| Protocol | VMAC | #VMACs supported | # VRIDs supported |
|---|---|---|---|
| Standard IPv4 VRRP (v2/v3) | 00-00-5E-00-01-{VRID} | 16 | 16 |
| Standard IPv6 VRRP (v3) | 00-00-5E-00-02-{VRID} | 16 | 16 |
| SLX-OS IPv4 VRRP-E (v2/v3) | 02:E0:52:00:01:<1-byte-mvrid> | 13 unique VMACs | mvrid is (((vrid-1) ÷16) + 1) with VRID ranging between 1 to 255 |
| SLX-OS IPv6 VRRP-E (v3) | 02:E0:52:00:02:<1-byte-mvrid> | 13 unique VMACs | mvrid is (((vrid-1) ÷ 16) + 1) with VRID ranging between 1 to 255 |
Note
The unique VMACs per hardware chip have to be used across all interfaces, virtual routing forwarding instances (VRFs), VRRP and VRRP-E sessions. VRIDs must not be used between VRRP/VRRP-E IPv4 and IPv6 sessions.