Wrapping it up
- A route map is a set of rules, processed on a top-down first-match basis.
- Each rule can be a permit (default) or deny. ...
- To define if a rule inside a route map matches, you use the match command. ...
- You can have multiple set commands inside the same rule.
- A rule with no match command will match anything.
Full Answer
What's new in route-map?
We introduced the following command: route-map . Enhanced support for dynamic and static route maps was added. We introduced the following commands: debug route, show debug route . We modified the following command: show route . Route maps are supported in multiple context mode.
What is the use of route map?
The route maps are mostly used when distributing the routes into the RIP, EIGRP or OSPF routing process. It is also used while generating the default route into the OSPF routing process. The route map also defines which of the routes from a specified routing protocol that are allowed to be redistributed into a target routing process.
What is route map in Cisco routers?
Let us see the concepts of the route maps and how powerful it is. One of the main purpose of the route map in the Cisco router is the customize traffic management beyond the routing tables boundaries. The route maps are mostly used when distributing the routes into the RIP, EIGRP or OSPF routing process.
How do I configure a route map?
A route map syntax is comprised of roughly 3 separate Cisco commands based on the accomplishing route map and type of process which calling it. When configuring the route map, follow the 5 step configuration process. Based on the application of the route map, additional configuration can also be needed, including with PBR or BGP communities.
What route map means?
A route map defines which of the routes from the specified routing protocol are allowed to be redistributed into the target routing process. Route maps have many features in common with widely known ACLs.
What is route map BGP?
Route maps allow you to configure a filtering criteria by defining a set of rules or match statements with a permit or deny condition. It includes a series of match statements to determine if a route matches the criteria defined in the statement and then apply the permit or deny rule accordingly.
What is the importance of route map?
This helps to alleviate the problem of driving back and forth between locations in a scattered way and makes sure you are making the most out of your time. Route Mapping apps also help to ensure you appear professional and on top of your game at all times by preventing tardiness.
What is difference between ACL and route map?
Thus, the main differences between a route-map and an ACL are: A route-map can perform matching operations based on very diverse attributes. An ACL performs matching based only on IP addresses, L4 protocols and ports and some additional variables typical for packet headers and contents.
What's a BGP prefix?
A prefix announced in BGP consists of the IPv4 or IPv6 address block being announced and also a path of AS numbers, indicating which ASNs the traffic must pass through to reach the announced address block. A BGP prefix would look something like (IPv4): 701 1239 42 206.24.
What is BGP prefix list?
A prefix list allows routing systems to determine which routes must be accepted when they peer with other networks. It includes IP prefixes with a match criteria that allows or denies route redistribution. It contains one or more ordered entries which are processed sequentially.
What are the benefits of route plan?
Drivers can reach jobs efficiently and quickly, resulting in increased productivity and happy customers. In addition optimized routing reduces fuel consumption and overtime costs by providing drivers with efficient routes and balanced schedules.
What are different types of maps?
Types of MapsGeneral Reference (sometimes called planimetric maps)Topographic Maps.Thematic.Navigation Charts.Cadastral Maps and Plans.
What is prefix list and route map?
When you apply a prefix-list, specify whether the list applies to learned routes (in) or advertised routes (out). A route is defined by the destination's IP address and network mask. By default, routes that do not match a prefix list are learned or advertised.
What is BGP local preference?
Local preference is the second BGP attribute and is used to choose the exit path for an autonomous system. The BGP preference has to be set inbound on routes being received to influence the outbound routing behaviour. A higher local preference is preferred and the default is 100.
What is route tagging?
A route tag is a 32-bit value attached to routes. Route tags are used to filter routes and apply administrative policies, such as redistribution and route summarization, to tagged routes. You can tag routes within a route map by using the set tag command.
What is Route Reflector in BGP?
Route reflectors have the special BGP ability to readvertise routes learned from an internal peer to other internal peers. So rather than requiring all internal peers to be fully meshed with each other, route reflection requires only that the route reflector be fully meshed with all internal peers.
What is route tagging?
A route tag is a 32-bit value attached to routes. Route tags are used to filter routes and apply administrative policies, such as redistribution and route summarization, to tagged routes. You can tag routes within a route map by using the set tag command.
What is BGP route filtering?
The BGP prefix-based outbound route filtering is enabled through the advertisement of ORF capabilities to peer routers. The advertisement of the ORF capability indicates that a BGP peer will accept a prefix list from a neighbor and apply the prefix list to locally configured ORFs (if any exist).
How do I show a route on a map?
Get directions & show routesOn your Android phone or tablet, open the Google Maps app . If you don't yet have the app, download it from the Play Store.Search for your destination or tap it on the map.In the bottom left, tap Directions .Choose your mode of transportation. For Driving or Transit.
When to use route maps?
Route maps are used when redistributing routes into an OSPF, RIP, EIGRP or BGP routing process. They are also used when generating a default route into an OSPF routing process. A route map defines which of the routes from the specified routing protocol are allowed to be redistributed into the target routing process.
How to identify route map order?
Route map entries are read in order. You can identify the order using the sequence_number argument, or the ASA uses the order in which you add route map entries.
What is the permit and deny clause in a route map?
Route maps can have permit and deny clauses. The deny clause rejects route matches from redistribution. You can use an ACL as the matching criterion in the route map. Because ACLs also have permit and deny clauses, the following rules apply when a packet matches the ACL:
Why do you not configure a set entry in a route map deny clause?
Do not configure a set entry in a route map deny clause because the deny clause prohibits route redistribution —there is no information to modify. A route map clause without a match or set entry does perform an action. An empty permit clause allows a redistribution of the remaining routes without modification.
What happens if a route map does not match a clause?
Route maps that are applied to redistribution behave the same way as ACLs: if the route does not match any clause in a route map then the route redistribution is denied, as if the route map contained a deny statement at the end. Permit and Deny Clauses. Match and Set Clause Values.
How does a router redistribute a route?
For each route that is being redistributed, the router first evaluates the match criteria of a clause in the route map. If the match criteria succeeds, then the route is redistributed or rejected as dictated by the permit or deny clause, and some of its attributes might be modified by the values set from the set commands. If the match criteria fail, then this clause is not applicable to the route, and the software proceeds to evaluate the route against the next clause in the route map. Scanning of the route map continues until a clause is found that matches the route or until the end of the route map is reached.
What order are route maps read?
Route map entries are read in order. You can identify the order using the sequence_number option, or the ASA uses the order in which you add route map entries.
How do route maps work?
The route maps are executed from the lowest sequence of number to the highest sequence. You can modify or edit the maps with the help of sequence number. You can use the route maps to deny or permit the information is true by match statements. If the match is found in the route map instance, the execution of the other further route map will stop.
What can you use route maps for?
You can use the route maps to create the policies based on the packet size, IP address, application, end system ID and protocol.
What is a route map in Cisco router?
One of the main purpose of the route map in the Cisco router is the customize traffic management beyond the routing tables boundaries. The route maps are mostly used when distributing the routes into the RIP, EIGRP or OSPF routing process. It is also used while generating the default route into the OSPF routing process. The route map also defines which of the routes from a specified routing protocol that are allowed to be redistributed into a target routing process. The route maps have so many features with widely known ACL. The common traits for both are as follows:
What is route_map_name?
Here, the route_map_name is also called as the map tag. It is the text-based route map name. In that the name is logically grouped and unique as well as defined all the route map policies. It is the name which is used to call a route map during the process and redistribution. The deny and permit keywords are always optional and a default keyword is permit. If a route map is called from the redistribution process, then the keywords are set to permit and a match criteria are met for a route map, a route is redistributed. If a keyword is set to deny, in same criteria, then a route might be denied. Suppose a route map is called from the policy routing statement, then match criteria is met for route map as well as a keywords are set to permit, then the packets might be policy routed. If a deny keyword is used, hen the packets are forwarded based on the normal route processes.
What is the default keyword for a route map?
The deny and permit keywords are always optional and a default keyword is permit. If a route map is called from the redistribution process, then the keywords are set to permit and a match criteria are met for a route map, a route is redistributed.
What does ACL mean in routing?
When applied to redistribution, the ACL determines if the specific route can or cannot be redistributed. The typical route map is not only permitted the redistributed route and also modify the information which are associated with the route, when they are redistributed into the other protocol.
Why is a route map important?
The route maps are like the duct tape for a network. It is not important because it can be used to mend or fix something broken, however, it can be applied to the numerous situation to overtake many issues. It is not the prettiest solutions, but it will be very effective. This route maps are like the "Then ... IF..." statements of various programming languages. "If" the specific condition is true and "then" will do something. The route maps enable to define routing policy which will considered before the router will examine the forwarding table and therefore it can define the routing policy which takes the precedence over the various route processes. Let us see the concepts of the route maps and how powerful it is.
What is a route map?
A route map is a map that shows the main roads in a particular area or the main routes used by buses, trains, and other forms of transport in a particular area. 2. countable noun. If you describe one thing as a route map for another thing, you mean that it provides a model showing the best way to achieve or describe it.
What does it mean when you describe a route map?
If you describe one thing as a route map for another thing, you mean that it provides a model showing the best way to achieve or describe it.
Why are route maps important?
Route-maps are very powerful but complicated tools for the redistribution of routes. They allow for very fine manipulation of routing information when it is redistributed between protocols. However, they can be dangerous and can create “blackholes” or suboptimal traffic flow in your network. You must design networks very carefully, if you are going to employ complex redistribution features between multiple routing protocols.
What command to use to configure route maps?
This document describes commands that you can use to configure route-maps that are applied with the redistribute command of dynamic routing protocols. This document also includes tips on route-map functions and advice on when route-map configuration is most beneficial.
How many routing protocols are there for redistribution?
This section describes the commands that are supported in route-maps attached in the redistribute command. There are seven routing protocols from which routes can be redistributed; however, there are only five to which redistribution can take place. Connected and static routes are not dynamic routing protocols and can only provide information to be redistributed into other protocols.
Why do you not configure a set command in a deny route-map clause?
Do not configure a set command in a deny route-map clause because the deny clause prohibits route redistribution —there is no information to modify. A route-map clause without a match or set command performs an action. An empty permit clause allows a redistribution of the remaining routes without modification.
Can you configure match and set in a route map?
You can configure match and set commands in a route-map that are not supported (or do not have effect) in a context where a route-map is applied (or intended to be applied at a later stage). An example of this situation can be the match length command used in a route-map applied to redistribution. In redistribution, a route-map is applied to each route installed into the routing table, by the protocol specified in the redistribute command. Therefore, when a router executes a route-map, the router interprets only the commands which make sense in the context of route-map application. In this example, the match length command mentioned in the redistribution route-map has no affect on redistribution. It remains in the configuration of the route-map, and it can be seen in the running configuration of the router. Route redistribution is not affected, however, whether this command is present in the route-map or not.
Does a router allow match and set?
In conclusion, the router allows the configuration of all kinds of match and set commands, but they should be applied logically to the situation. Otherwise, the configuration might be very confusing or might perform incorrect tasks.
Is the +/- form of redistribution route-maps supported?
The +/- form of this command is not currently supported in redistribution route-maps, and it is actually interpreted as the set metric command with the sign omitted. For example, consider this route-map:
How does a route map work?
The router processes the rules of a route map in a top-down approach, from the lowest ID to the highest. As soon as we have a match to a rule, we execute that rule and exit. The router won’t execute the following rules. We can summarize this behavior as top-down first-match.
What are the two common uses for route maps?
Two common uses for route maps are redistribution and PBR.
What is an ACL route map?
You can think of a route map like an advanced ACL. The Access Control List matches an IP address, and performs two actions: permit or deny. In fact, an ACL can process any IP address permit or deny it, according to its rules. Because of that, ACLs are a natural choice for blocking or permitting traffic. However, you can use them in other applications as well. For example, you can use them to define which IP addresses the router should NAT.
What can a route map match?
A route map can match on metrics, on IP addresses, prefix length, routing protocol, and more. With all this power, how do we use a route map?
How to use a route map for redistribution?
Using a route map for redistribution is simple. First, you need to enter the configuration of the protocol that will receive the routes. Then, you use the redistribute command to define the protocol that will generate the route to import. Just after that, you use the keyword route-map and specify the route map name. Take a look at the following example.
What are the three rules of a route map?
Just like an ACL, a route map is a set of rules. Each rule has just three items: the action type, the match clause, and the set clause.
How to determine if a rule inside a route map matches?
To define if a rule inside a route map matches, you use the match command. Matching multiple items on the same line means joining them with a logical OR, using multiple match commands means joining them with a logical AND.
What is a route map?
Route maps are similar to access lists; they both have criteria for matching the details of certain packets and an action of permitting or denying those packets. This chapter explains the basics of Route Maps. Included are sample exercises to help you practice administration and use of Route Maps.
How is a packet passed?
A packet or route is passed sequentially through route map statements. If a match is made, any set statements are executed and the permit or deny action is executed. As with access lists, processing stops when a match is made and the specified action is executed; the route or packet is not passed to subsequent statements. Consider the route map in Example 14-5.
Why is bulk traffic segregated?
The purpose of segregating bulk and interactive traffic, as demonstrated in the last example, is so that the small packets characteristic of interactive traffic do not become delayed by the large packets characteristic of bulk traffic. The problem with the approach in this example is that if many types of traffic must be segregated, the access lists identifying the traffic by destination port might become prohibitively large.
What does "deny" mean in routing?
The behavior of a "deny" action depends on whether the route map is being used for policy routing or for redistribution. If a route map is being used for redistribution and a route matches a statement with a deny action, the route will not be redistributed.
What happens if a route does not match statement 10?
If a route does not match statement 10, it will be passed to statement 20. If a match is made at statement 20, the set command will be executed and the route will be permitted. The matched route will not be passed on to statement 30.
When to use standard IP access list?
Standard IP access lists are used when policy routing by source address only. To route by both source and destination, an extended IP access list is used. The configuration in Example 14-12 causes packets from any subnet to host 172.16.1.1 to be forwarded to Lucy, whereas packets from host 172.16.7.1 to host 172.16.1.2 are forwarded to Pigpen. All other packets are routed normally.
Do route maps affect anything?
Like access lists (see Appendix B, "Tutorial: Access Lists"), route maps by themselves affect nothing; they must be "called" by some command. The command will most likely be either a policy routing command or a redistribution command. Policy routing will send packets to the route map, whereas redistribution will send routes to the route map. The case studies in this section demonstrate the use of route maps for both redistribution and policy routing.