Coverage Primarily based Routing (PBR): Methods to Configure?

Routing is a crucial side of networking. Routing is the method to find vacation spot networks, promoting them, decide the very best path for visitors and preserve route info. Routing happens at layer 3 and there are a number of protocols out there on layer 3 and so they carry out a typical set of comparable duties reminiscent of promote, construct native route tables in reminiscence, select the very best path.

Alternate to traditional routing a extra flexi method to routing is obtainable by PBR or Coverage Primarily based Routing for higher management and administration of community visitors by community directors. 

At present we glance extra intimately about coverage based mostly routing, the way it works, its options, structure elements, benefits and use instances and so forth.

Because the identify suggests in Coverage based mostly routing knowledge packets are routed or forwarded utilizing insurance policies or filters. Community directors can apply selective insurance policies based mostly on particular set of parameters reminiscent of supply and vacation spot IP handle, supply or vacation spot port, visitors sort, protocols, entry lists, packet measurement, or another standards to route packets on consumer outlined routes. The target is to make community agile and versatile. By defining routing behaviour based mostly on utility attributes, community directors can optimize how bandwidth get utilized by most business-critical purposes. 

Conventional routing which is predicated on the vacation spot of visitors has limitations. With the appearance of cloud computing, mobility and web-based purposes there’s a want for extra agile networks which know every utility visitors sort traversing the community. PBR handles purposes individually to successfully prioritize , segregate, and route visitors with out compromising its availability and efficiency. 

How does PBR work?

PBR is a substitute for routing protocols which allow you to configure a coverage for unicast visitors flows to supply extra management over routing than a routing protocol does and keep away from the necessity to configure interface stage visitors classification. PBR gives equal entry, protocol delicate routing, supply delicate routing, interactive slightly than batch routing, routing based mostly on devoted hyperlinks. 

PBR utilized route maps might be configured to permit or deny paths based mostly on the id of a particular finish system , an utility protocol, or packet measurement or mixture of any of those values. Classification of visitors based mostly on standards of prolonged checklist, set IP priority bits and so forth.

PBR applies route map to all ingress unicast visitors obtained on a PBR enabled interface. PBR can’t be utilized to egress visitors or to multicast visitors. If the ingress unicast visitors doesn’t match the route map, then route map applies to all configured set clauses. Routing protocols ahead visitors which match a route map deny assertion and visitors which doesn’t match any route map allow statements.

Benefits of PBR 

• Prioritization of purposes by selecting excessive bandwidth, low latency hyperlinks for important purposes.
• Load sharing by making a fallback hyperlink for important visitors in case foremost hyperlink carrying important utility visitors suffers an outage.
• Segregation of visitors for deep evaluation or inspection. 
• Controlling move of subscriber visitors in service supplier networks by way of visitors administration insurance policies and guidelines based mostly on subscriber profiles. 
• Present assured service stage agreements (SLAs) for supply of the particular visitors to make sure it receives acceptable precedence, routing and bandwidth to make sure enhanced consumer expertise.
• Ship particular purposes for WAN optimization. Classify visitors based mostly on purposes, ship to WAN optimizer to hurry up entry to important purposes and knowledge. 

Methods to configure PBR?

To configure PBR on an interface following instructions are utilized in world configuration mode.

Step 1 Router(config)# route-map map-tag [permit | deny] [sequence-number] 

This command is used to outline a route map to manage the place packets are output. 

Step 2 Router(config-route-map)# match size min max 

Router(config-route-map)# match ip handle identify […access-list-number | name]

Specifies match standards for size and ip handle 

Size matches stage 3 size of packet

IP handle matches supply or vacation spot IP handle permitted by a number of customary or prolonged entry lists

Default is to use to all packets

Step 3 Router(config-route-map)# set ip priority [number | name]

Router(config-route-map)# set ip df

Router(config-route-map)# set ip vrf vrf_name

Router(config-route-map)# set ip next-hop ip-address [… ip-address]

Router(config-route-map)# set ip next-hop recursive ip-address [… ip-address]

Router(config-route-map)# set interface interface-type interface-number [… type number]

Router(config-route-map)# set ip default next-hop ip-address [… ip-address]

Router(config-route-map)# set default interface interface-type interface-number [… type …number]

Specify motion taken on each packet which is in scope of standards 

Priority – set priority worth in ip header 

Df set the ‘don’t fragment’ bit in ip header

Vrf units VPN routing and forwarding occasion

Subsequent-hop – subsequent hop to which route the packet

Subsequent-hop recursive – set subsequent hop to which route packet if hop is a router which isn’t adjoining

Interface – output interface for packet

Default next-hop – set subsequent hop to route packet if there is no such thing as a express path to vacation spot

Default interface – set output interface for packet if there is no such thing as a express path to vacation spot 

Step 4 Router(config-route-map)# interface interface-type interface-number

Specify interface and put router into interface configuration mode

Step 5 Router(config-if)# ip coverage route-map map-tag

Establish route map to make use of for PBR 

Proceed Studying:

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