In this video we cover:
- What is HSRP
- What is GLBP
- What is VRRP
- HSRP Lab
These topics are in the new CCNA exam so please do learn the theory and how to configure them all. HSRP configuration as well as GLBP and VRRP are covered in the video also. We don't have the space to put 30 pages of notes in here so please check our our Cisco CCNA video course or our Cisco CCNA Simplified book.
Here are the main points you may be tested on in any exam.
Hot Standby Router Protocol – HSRP
- HSRP is a Cisco-proprietary First Hop Redundancy Protocol (FHRP)
- Two versions are HSRP are supported in Cisco IOS software: versions 1 and 2
- HRSP version 1 is the default HSRP version
- HSRP version 1 restricts the number of configurable HSRP groups to 255
- HSRP version 1 sends updates to Multicast group address 224.0.0.2 using UDP port 1985
- HSRP version 2 uses the new Multicast address 224.0.0.102
- The version 2 packet format uses a Type/Length/Value (TLV) format
- HSRP version 2 packets are ignored by gateways running version 1
- HSRP version 1 is not capable of advertising or learning millisecond timers; version 2 is
- HSRP version 2 numbers have been extended from 0 to 4095
- HSRP version 2 includes a 6-byte Identifier field that contains the router MAC address
HSRP version 1 uses the MAC range 0000.0C07.ACxx - HSRP version 2 uses the MAC range 0000.0C9F.F000 to 0000.0C9F.FFFF
- The default HSRP gateway priority is 100; the range is 1 – 255
- HSRP routers exchange three types of messages: Hello/Coup/Resign Messages
- By default, preemption is disabled for HSRP
- HSRP interfaces transition through several states, which are:
1.Disabled
2. Init
3. Listen
4. Speak
5. Standby
6. Active - HSRP uses a default plain-text authentication password of ‘cisco'
- HSRP supports plain text and MD5 authentication
- MD5 authentication can be configured with or without key chains
- HSRP supports interface tracking configuration
- Multiple HSRP groups can be configured on the gateway for load balancing
Virtual Router Redundancy Protocol – VRRP
- VRRP is an open standard First Hop Redundancy Protocol, similar to HSRP
- VRRP is defined in RFC 2338, which was made obsolete by RFC 3768
- VRRP sends advertisements to the Multicast destination address 224.0.0.18
- VRRP uses IP protocol number 112
- VRRP uses MAC addresses in the range 00-00-5e-00-01xx
- VRRP elects a virtual router master and virtual router backup
- You configure up to 255 virtual routers on an interface
- The number of supported virtual routers that can be configured depends on:
1. Router processing capability
2. Router memory capability
3. Router interface support of multiple MAC addresses - The default VRRP priority value is 100; the valid range is 1 – 254
- By default, preemption is enabled for VRRP
- The default VRRP version is version 2; there is no version 1
- VRRP version 3 is still in the draft stage
- The virtual router master sends advertisements to other routers in the same group
- Like HSRP, VRRP supports both plain text and MD5 authentication
Gateway Load Balancing Protocol – GLBP
- GLBP allows multiple gateways in the same GLBP group to actively forward traffic
- GLBP gateways communicate via Hello messages that are sent every 3 seconds
- GLBP Hello messages are sent to the Multicast address 224.0.0.102, using UDP port 3222
- GLBP group members elect one gateway to be the AVG for that group
- The other gateways in the GLBP group provide backup for the AVG in case it fails
- The AVG answers all ARP requests for the virtual router address
- In addition, the AVG assigns a virtual MAC address to each member of the GLBP group
- Each gateway is an AVF for the virtual MAC address it has been assigned
- A GLBP group allows up to four virtual MAC addresses to be used per group
- A primary virtual forwarder is assigned a virtual MAC address by the AVG
- A secondary virtual forwarder is one that has learned the virtual MAC address
- GLBP uses two timers to migrate away from an old forwarder address:
1. The redirect timer
2. The timeout timer - By default, GLBP preemption is disabled; however, this feature can be manually enabled
- GLBP uses a weighting scheme to determine the forwarding capacity of each gateway
- By default, each gateway is assigned a default weight of 100
- GLBP supports three different load sharing methods:
1. Host-dependent
2. Round Robin
3. Weighted - The client cache contains information about hosts using a GLBP group as default gateway
- The maximum number of cache entries that may be stored can be up to 2000
- In production environments, is recommended that this number never exceed 1000
- GLBP supports plain-text and MD5 authentication
HSRP Configuration Labs
Please choose one or both. We have a hard, multiple switch HSRP configuration lab or a mini lab so you can try out the commands.
HSRP Mini Lab (right click to download)
HSRP Hard Lab (right click to download)
Our CCNA video course has a ton of tuition, mini labs, full labs, exams and even and entire step-by-step coaching program. You can access live Cisco routers and switches 24/7 as a member. No extra charge.
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