{"id":761,"date":"2024-12-01T03:17:24","date_gmt":"2024-12-01T00:17:24","guid":{"rendered":"https:\/\/itgen.itbumper.com\/?page_id=761"},"modified":"2024-12-01T03:21:35","modified_gmt":"2024-12-01T00:21:35","slug":"0021_cisco-fhrp","status":"publish","type":"page","link":"https:\/\/itgen.itbumper.com\/?page_id=761","title":{"rendered":"0021_Cisco: FHRP"},"content":{"rendered":"<p style=\"text-align: justify;\"><strong>FHRP<\/strong> (First Hop Redundancy Protocol) is a group of protocols that provide high availability for the default gateway in a local network. The primary goal of FHRP is to automatically switch between multiple routers or Layer 3 switches in case the primary device fails.<\/p>\n<p style=\"text-align: justify;\"><strong>Main FHRP protocols:<\/strong><\/p>\n<ul style=\"text-align: justify;\">\n<li><strong>HSRP<\/strong> (Hot Standby Router Protocol) \u2014 Cisco proprietary.<\/li>\n<li><strong>VRRP<\/strong> (Virtual Router Redundancy Protocol) \u2014 open standard.<\/li>\n<li><strong>GLBP<\/strong> (Gateway Load Balancing Protocol) \u2014 Cisco proprietary with load balancing.<\/li>\n<\/ul>\n<p style=\"text-align: justify;\"><strong>Purpose:<\/strong> Ensure continuous network access and minimize downtime during device failures.<\/p>\n\n<div class=\"wp-block-syntaxhighlighter-code \"><pre class=\"brush: bash; title: ; notranslate\" title=\"\">\n# FHRP - First Hop Redurancy Protocol\n\n#FHRP\t|\tTerminology\t\t| Multicast IP  | Virtual MAC\t| Cisco?\n----------------------------------------------------------------------\n# HSRP\t| Active\/Standbay\t| v1:224.0.0.2  | 0000.0c07.acXX\t| Yes\n#\t\t|\t\t\t\t\t| v2:224.0.0.102| 0000.0c9f.fXXX\t|\n# VRRP\t| Master\/Backup\t\t| 224.0.0.18\t| 0000.5e00.01XX\t| No\n#\t\t|\t\t\t\t\t|\t\t\t\t|\t\t\t\t\t|\n# GLBP\t|   AVG\/AVF\t\t\t| 224.0.0.102\t|0007.b400.XXYY\t\t| Yes\n----------------------------------------------------------------------\n\n\n# R1 (Active)&lt;==Hello messages==&gt;R2 (Standbay)\n#\t.254\t\t\t\t\t\t\t.253\n#\t\t\t\\\t\t\t\t\t\/\n#\t\t\t \\\t\t\t\t   \/\n#\t\t\t  \\\t\t\t\t  \/\n#\t\t\t   \\\t\t\t \/\n#\t\t\t    \\\t\t\t\/\n#\t\t\t\t\t VIP \t\t&lt;-has own virtual MAC\n#\t\t\t\t\t.252\n#\n#\t\t\t\t\/\t\t\t\\\n#\t\t\t   \/ \t\t     \\\n#\t\t\t  \/\t\t\t\t  \\\n#  set as a default GW | set as a default GW\n#\n#Gratuitous ARP: ARP replies sent without being requested (no ARP request messages was recieved)\n#Then the Active router failed, the Standbay router will not recieved Hello packet and send a Gratuitous ARP\n#packet and it will update all FDB tables on all switches in their domain.\n#\n#By default, if router back online it doesn`t become an Active router.\n#You have to configure &quot;preemption&quot;, so the old Active router does not take back its old role.\n\n-----------------------------------------------------------------------\n#HSRP (Cisco) Hot Standbay Router Protocol\n\n#v1 - \n#v2 - support IP v6 and increase the number of groups tha can be configured\n#Active and Standbay routers are elected\n#Multicats address for v1 = 224.0.0.2\n#Multicats address for v2 = 224.0.0.102\n#Virtual MAC for v1 = 0000.0c07.acXX, where XX is a group number\n#Virtual MAC for v2 = 0000.0c9f.fXXX, where XXX is a group number\n#\n#In a situation with multiple subnets\/VLANs, you can configure a different Active router in each\n#subnets\/VLANs to load balance.\n\n#VRRP - Virtual Router Redurancy Protocol\n#Open standart\n#Master and Backup routers are elected\n#Multicats address = 224.0.0.18\n#Virtual MAC = 0000.5e00.01XX, where XX is VRRP group number\n#Example: For the group with number 200=0xc8, MAC address will be 0000.5e00.01c8\n\n#GLBP - Gateway Load Balancing Protocol (Cisco)\n#Load balancing among multiple routers within a single subnet\n#An AVG (Active Virtual Gateway) is elected\n#Up to 4 AVFs (Active Virtual Forwarders) are assingned by the AVG (the AVG itself can be an AVF too)\n#Each AVF acts as a default gateway for a portion ot the hosts in the subnet.\n#Multicats address = 224.0.0.102\n#Virtual MAC = 0007.b400.XXYY, where XX is a GLBP group number, YY - AVF number\n\n\n#CONFIGURING HSRP\n#R1,R2,SW1,SW2\n#R1\n#int g0\/0 - connected to a SW1,IP addr = 172.16.0.253\/24\n#int g1\/0  - connected to a cloud, IP addr = 203.0.113.1\n#\n#R2\n#int g0\/0 - connected to a SW2,IP addr = 172.16.0.252\/24\n#int g1\/0  - connected to a cloud, IP addr = 203.0.113.5\n#VIP = 172.16.0.254\/24\t\n#SW1 connected to SW2\n\n#R1\n\t\tint g0\/0\n\t\t\tstandbay version 2\n\t\t\tstandbay 1 ip 172.16.0.254\n\t\t\tstandbay 1 priority &lt;0-255&gt;\n#Active router is determinated in this order:\n#Highest priority (by default 100)\n#Highest IP address\n\t\t\tstandbay 1 priority 200\n\t\t\tstandbay 1 preempt\t\t\t#need to use if you want R1 always become Active, after back online\n\n#R2\n\tint g0\/0\t\n\t\tstandbay version 2\n\t\tstandbay 1 ip 172.16.0.254\n\t\tstandbay 1 priority 50\n\t\tstandbay 1 preempt\n#Version must be the same on the routers\n\tshow standbay\n<\/pre><\/div>","protected":false},"excerpt":{"rendered":"<p>FHRP (First Hop Redundancy Protocol) is a group of protocols that provide high availability for the default gateway in a local network. The primary goal of FHRP is to automatically switch between multiple routers or Layer 3 switches in case the primary device fails. Main FHRP protocols: HSRP (Hot Standby Router Protocol) \u2014 Cisco proprietary. &hellip; <a href=\"https:\/\/itgen.itbumper.com\/?page_id=761\" class=\"more-link\">Continue reading<span class=\"screen-reader-text\"> &#8220;0021_Cisco: FHRP&#8221;<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"categories":[],"tags":[],"_links":{"self":[{"href":"https:\/\/itgen.itbumper.com\/index.php?rest_route=\/wp\/v2\/pages\/761"}],"collection":[{"href":"https:\/\/itgen.itbumper.com\/index.php?rest_route=\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/itgen.itbumper.com\/index.php?rest_route=\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/itgen.itbumper.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/itgen.itbumper.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=761"}],"version-history":[{"count":2,"href":"https:\/\/itgen.itbumper.com\/index.php?rest_route=\/wp\/v2\/pages\/761\/revisions"}],"predecessor-version":[{"id":768,"href":"https:\/\/itgen.itbumper.com\/index.php?rest_route=\/wp\/v2\/pages\/761\/revisions\/768"}],"wp:attachment":[{"href":"https:\/\/itgen.itbumper.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=761"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/itgen.itbumper.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=761"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/itgen.itbumper.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=761"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}