It is somewhat irritating that we have three protocols which accomplish nearly the same tasks. HSRP and VRRP are practically identical, while GLBP expands their functionality to offer load balancing. Interestingly, VRRP does not support IPv6, as IPv6 can provide more robust router discovery through its Neighbor Discovery Protocol. Cisco has included IPv6 support in HSRP and GLBP, though.
|
Protocol |
HSRP (Hot Standby Router protocol) |
VRRP (Virtual Redundancy Router Protocol) |
GLBP (Gateway Load Balancing Protocol) |
|
|
Router role |
– 1 active router.- 1 standby router.- 1 or more listening routers. |
– 1 master router.- 1 or more backup routers. |
– 1 AVG (Active Virtual Gateway).- up to 4 AVF routers on the group (Active Virtual Forwarder) passing traffic.- up to 1024 virtual routers (GLBP groups) per physical interface. |
|
|
– Use virtual ip address. |
– Can use real router ip address, if not, the one with highest priority become master. |
– Use virtual ip address. |
||
|
Scope |
Cisco proprietary |
IEEE standard |
Cisco proprietary |
|
|
Election |
Active Router: |
Master Router: (*) |
Active Virtual Gateway: |
|
|
Optimization features |
Tracking |
yes |
yes |
yes |
|
Preempt |
yes |
yes |
yes |
|
|
Timer adjust |
yes |
yes |
yes |
|
|
Traffic type |
224.0.0.2 – udp 1985 (version1) |
224.0.0.18 – IP 112 |
224.0.0.102 udp 3222 |
|
|
Timers |
Hello – 3 seconds |
Advertisement – 1 second |
Hello – 3 seconds |
|
|
(Hold) 10 seconds |
(Master Down Interval)3 * Advertisement + skew time |
(Hold) 10 seconds |
||
|
(Skew time)(256-priority) / 256 |
||||
|
Load-balancing functionality |
– Multiple HSRP group per interface/SVI/routed int. |
– Multiple VRRP group per interface/SVI/routed int. |
Load-balancing oriented- Weighted algorithm.- Host-dependent algorithm. – Round-Robin algorithm (default). |
|
|
Requires appropriate distribution of Virtual GW IP per Clients for optimal load-balancing.(generally through DHCP) |
Requires appropriate distribution of Virtual GW IP per Clients for optimal load-balancing.(generally through DHCP) |
Clients are transparently updated with virtual MAC according to load-balancing algorithm through ARP requesting a unique virtual gateway. |
||
HSRP vs. VRRP
1. HSRP is a propriety protocol developed by CISCO, whereas VRRP is a non-propriety
protocol created by IEFT.
2. HSRP was created in an earlier year compared to the more recent VRRP.
3. VRRP has a faster timer for its default hello, and a faster hold timer, as opposed to
the slower HSRP timers.
4. VRRP’s standby speaker cannot send hellos like the HSRP protocols.
HSRP :
This also utilizes a default hello countdown timer for 3 seconds, along with a hold timer
that spans for 10 seconds.
VRRP :
Is a non-propriety protocol developed and invented by IEFT, back in 1999. This protocol is said to work for a wide range of systems. It even boasts of a faster timer of 1 second for its default hello, and a 3-second hold timer as well. Moreover, it has been observed that VRRP’s standby speaker is not able to send hellos, as opposed to its availability in the HSRP protocol.
In regards to VRRP, there is a backup router that supports the role of the master router, in the event that
the latter fails to function.
* If the group VRRP Virtual IP on the master (higher priority) is the real IP configured on a different VRRP (Backup with lower priority) IOS will manage to make the VRRP router with the real IP, the master, by setting its priority to 255, knowing that the configurable range is [1-254].
Hot Standby Router Protocol (HSRP) is a Cisco proprietary redundancy protocol for establishing a fault-tolerant default gateway.
Primary-Router-Config :
interface GigabitEthernet0/0
description Comms-Primary-Router
ip address 10.10.10.1 255.255.255.0
ip nat inside
ip inspect myfw in
ip virtual-reassembly
duplex auto
speed auto
standby 1 ip 10.10.10.3
standby 1 timers msec 500 2
standby 1 priority 110
standby 1 preempt delay minimum 1
standby 1 authentication LocalLan
standby 1 name Group1
standby 1 track 4 decrement 100
standby 1 track 5 decrement 15
!
!
interface GigabitEthernet0/1
description WAN_Interface
ip address 1.1.1.1 255.255.255.0
ip nat outside
ip virtual-reassembly
duplex auto
speed auto
!
!
track 4 interface GigabitEthernet0/0 line-protocol
!
track 5 interface GigabitEthernet0/1 line-protocol
!
Secondary-Router-Config :
interface GigabitEthernet0/0
description Comms-Seondary-Router
ip address 10.10.10.2 255.255.255.0
ip nat inside
ip inspect myfw in
ip virtual-reassembly
duplex auto
speed auto
standby 1 ip 10.10.10.3
standby 1 timers msec 500 2
standby 1 preempt delay minimum 1
standby 1 authentication LocalLan
standby 1 name Group1
standby 1 track 4 decrement 100
standby 1 track 5 decrement 15
!
!
interface GigabitEthernet0/1
description WAN_Interface
ip address 1.1.1.1 255.255.255.0
ip nat outside
ip virtual-reassembly
duplex auto
speed auto
!
!
track 4 interface GigabitEthernet0/0 line-protocol
!
track 5 interface GigabitEthernet0/1 line-protocol
HSRP track ip route
config t
int g0/1
track 1 ip route 10.1.20.0/24 reachability
Track the route so if the main interface would drop the tunnel would still show up/up but would drop its EIGRP adjacency which would drop the route.