GLBP
This is a Cisco proprietary FHRP. The v4 and v6 exist for IOS, but v6 is missing for IOS-XE.
Terms
GLBP — Gateway Load Balancing Protocol
- Cisco Proprietary
- Supports 4 active forwarding instances
AVG — Active Virtual Gateway
- The AVG is responsible for answering incoming ARP for the VIP
- Can reply with a different MAC addresses to load balance
- Highest priority router is the AVG
AVF — Active Virtual Forwarder
- Two states {Active, Listen}
- All AVFs have their own mac and forwarding traffic destined towards that MAC
- 4 max
Details
- Multicast
- 224.0.0.102
- UDP 3222
- MD5 is supported
- Default timers: 3s / 10s
Example
R1# show glbp brief
Interface Grp Fwd Pri State Address Active router Standby router
Gi0/0 12 - 100 Active 192.168.12.12 local 192.168.12.2
Gi0/0 12 1 - Active 0007.b400.0c01 local -
Gi0/0 12 2 - Listen 0007.b400.0c02 192.168.12.2 -
Config
interface GigabitEthernet0/0
ip address 192.168.12.1 255.255.255.0
!
glbp 12 ip 192.168.12.12
glbp 12 priority 100
glbp 12 preempt
!
glbp 12 weighting 100
glbp 12 load-balancing round-robin