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The answer to this obstacle will depend on the kind of potential customers distinctions you're looking for to help make, as well the model of IOS you are running inside your routers. CCIE Voice Training

There ought to be some thing that defines the different different types of website traffic that you simply want to prioritize. Normally, the easier the distinctions are to create, the better. It is because all the checks get router sources and introduce processing delays. The most common principles for distinguishing around potential customers variations utilize the packet's input interface and very simple IP header details like as TCP port quantities. The next examples display best ways to set an IP Precedence price of speedy (2) for all FTP manage targeted visitors that arrives by means of the serial0/0 interface, and an IP Precedence of priority (1) for all FTP information site traffic. This distinction is possible due to the fact that FTP manage website traffic usages TCP port 21, and FTP info uses port twenty.

The brand new technique for configuring this usages course maps. Cisco earliest released this feature in IOS Edition 12.0(5)T. This method 1st defines a class-map that specifies how the router will recognize this type of site visitors. It then defines a policy-map that truly makes the variations with the packet's TOS industry:

Router#configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
Router(config)#access-list 101 permit any eq ftp any
Router(config)#access-list 101 permit any any eq ftp
Router(config)#access-list 102 permit any eq ftp-data any
Router(config)#access-list 102 permit any any eq ftp-data
Router(config)#class-map match-all ser00-ftpcontrol
Router(config-cmap)#description branch ftp control traffic
Router(config-cmap)#match input-interface serial0/0
Router(config-cmap)#match access-group 101
Router(config-cmap)#exit
Router(config)#class-map match-all ser00-ftpdata
Router(config-cmap)#description branch ftp data traffic
Router(config-cmap)#match input-interface serial0/0
Router(config-cmap)#match access-group 102
Router(config-cmap)#exit
Router(config)#policy-map serialftppolicy
Router(config-pmap)#description branch ftp traffic policy
Router(config-pmap)#class ser00-ftpcontrol
Router(config-pmap-c)#set ip precedence immediate
Router(config-pmap-c)#exit
Router(config-pmap)#class ser00-ftpdata
Router(config-pmap-c)#set ip precedence priority
Router(config-pmap-c)#exit
Router(config-pmap)#exit
Router(config)#interface serial0/0
Router(config-if)#ip route-cache policy
Router(config-if)#service-policy input serialftppolicy
Router(config-if)#exit
Router(config)#end
Router#

For previously IOS versions, where by class-maps had been not obtainable, you've to make use of policy-based routing to alter the TOS discipline inside of a packet. Applying this coverage towards the interface tells the router to utilize this policy to check all incoming packets on this interface and rewrite those that match the route map:Router#configure terminal

Enter configuration commands, one per line. End with CNTL/Z.
Router(config)#access-list 101 permit any eq ftp any
Router(config)#access-list 101 permit any any eq ftp
Router(config)#access-list 102 permit any eq ftp-data any
Router(config)#access-list 102 permit any any eq ftp-data
Router(config)#route-map serialftp-rtmap permit 10
Router(config-route-map)#match ip address 101
Router(config-route-map)#set ip precedence immediate
Router(config-route-map)#exit
Router(config)#route-map serialftp-rtmap permit 20
Router(config-route-map)#match ip address 102
Router(config-route-map)#set ip precedence priority
Router(config-route-map)#exit
Router(config)#interface serial0/0
Router(config-if)#ip policy route-map serialftp-rtmap
Router(config-if)#ip route-cache policy
Router(config-if)#exit
Router(config)#end
Router#

Well before one can tag a packet for wonderful treatment, you might have to obtain a particularly very clear strategy of what styles of visitors require special treatment method, coupled with specifically what sort of exclusive cure they are going to will need. While in the illustration, we have now made a decision to give a distinctive priority to FTP targeted traffic acquired on the exact serial interface. We display how one can do this using both the previous and new configuration techniques.
This will seem to get a relatively synthetic illustration. Upon all, why would you treatment about tagging inbound page views that you simply have currently acquired from a low-speed interface? Realistically, on the list of most vital concepts for implementing QoS inside a network is always that you really should generally tag the packet as early as you possibly can, preferably with the edges from the network. Then, as it passes from the network, every router only has to take a look at the tag, and won't should do any extra classification. In cases like this, we would make sure which the FTP traffic returning in the other course is tagged by number one router that gets it. Therefore the outbound site traffic has previously been tagged, and it's a waste of router assets to reclassify the outbound packets.

Numerous organizations definitely just take this idea of marking on the edges a single action additionally, and remark just about every obtained packet. This facilitates to make sure that people aren't requesting distinctive QoS privileges they aren't permitted to own. Nonetheless, you need to be mindful of this considering it may now and again disrupt authentic markings. For example, a real-time application will probably use RSVP to order bandwidth in the network. It happens to be significant the packets for this software possess the ideal Expedited Forwarding (EF) DSCP marking or perhaps the network may not deal with them competently. All the same, additionally you do not need to let other non-real-time purposes from this identical source possess the same exact EF concern stage. So, for everybody who is heading to configure your routers to remark all incoming packets for the edges, always make sure you realize what incoming markings are reputable.

In that circumstance, the routers are jogging DLSw to bridge SNA targeted traffic by an IP network. So the routers on their own honestly build the IP packets. This makes an extra problem seeing that there is no incoming interface. Making sure that recipe uses localized policy-based routing. The fact the router results in the packets also provides it an important gain as it doesn't have to think about any DLSw packets which may just occur to go through.

The benefits from the more recent class-map technique are not evident in this particular example, but one of several initially major advantages appears if you want to employ the more modern day DSCP tagging scheme. Because the mature policy-based routing way does not right assistance DSCP, you might have to faux it by environment both the IP Precedence additionally, the TOS independently as follows.

Router(config)#route-map serialftp-rtmap permit 10
Router(config-route-map)#match ip address 115
Router(config-route-map)#set ip precedence immediate
Router(config-route-map)#set ip tos max-throughput

In this case, the packet will wind up with an IP Precedence value of immediate, or 2 (010 in binary), and TOS of max-throughput, or 4 (0100 in binary).

Doing the same thing with the class-map method is much more direct:

Router(config)#policy-map serialftppolicy
Router(config-pmap)#class serialftpclass
Router(config-pmap-c)#set ip dscp af21

Class-maps can even be helpful afterwards in this chapter when we speak about class-based weighted truthful queuing and class-based site traffic shaping.
It can be crucial to notice that through this whole instance, we have now only put a extraordinary price into the packet's TOS or DSCP discipline. This, by alone, won't influence how the packet is forwarded because of the network. To accomplish that, you must be certain that as each and every router within the network forwards these marked packets, the interface queues will react appropriately to this info.

Finally, we should observe that whilst this recipe reveals two helpful tactics of marking packets, working with Dedicated Entry Rate (Autobus) attributes. Autobus tends for being way more effective on larger velocity interfaces.