working in your routers
The answer to this problem depends upon the sort of site traffic distinctions you are looking for to create, also the version of IOS you might be jogging with your routers.
There should be anything that defines the various types of site visitors which you desire to prioritize. Typically, the easier the distinctions are to generate, the higher. This is because each of the assessments consider router resources and introduce processing delays. The most common policies for distinguishing concerning targeted traffic variations make use of the packet's input interface and effortless IP header details such as TCP port quantities. The next examples exhibit a way to set an IP Precedence value of rapid (2) for all FTP handle site traffic that arrives by using the serial0/0 interface, and an IP Precedence of concern (1) for all FTP data potential customers. This distinction is possible on the grounds that FTP management page views works by using TCP port 21, and FTP data takes advantage of port twenty.
The new process for configuring this works by using class maps. Cisco first of all launched this function in IOS Version 12.0(five)T. This process to begin with defines a class-map that specifies how the router will establish this type of visitors. It then defines a policy-map that really helps make the alterations for the packet's TOS subject:
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 variations, just where class-maps happen to be not to choose from, you could have to work with policy-based routing to alter the TOS industry in a packet. Applying this coverage on the interface tells the router to use this coverage to test 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#
Earlier than it's possible to tag a packet for extraordinary procedure, you will have to get a particularly apparent concept of what kinds of traffic ought wonderful remedy, as well as exactly what sort of exceptional procedure they will might need. Inside illustration, we have made a decision to give a unique priority to FTP potential customers obtained on the particular serial interface. We display simple tips to do that working with both equally the previous and new configuration strategies.
This will likely appear to get a rather artificial illustration. Upon all, why would you care about tagging inbound targeted visitors that you simply have currently obtained from a low-speed interface? Ultimately, one of the many most significant ideas for employing QoS within a network is usually that you ought to consistently tag the packet as early as you can, ideally at the edges of this network. Then, because it passes through the network, each and every router only needs to take a look at the tag, and doesn't really need to do any added classification. In this instance, we would assure the FTP customers returning from the other course is tagged with the first of all router that receives it. So the outbound traffic has previously been tagged, and it is a waste of router sources to reclassify the outbound packets.
A good number of organizations basically take this concept of marking in the edges one particular stage additional, and remark any received packet. This aids to make certain that people aren't requesting particular QoS privileges which they aren't authorized to acquire. However, you should be careful of this considering it can sometimes disrupt reputable markings. One example is, a real-time software may well use RSVP to order bandwidth from the network. Its essential the packets for this application hold the ideal Expedited Forwarding (EF) DSCP marking or the network may not cope with them effectively. Though, additionally you don't desire to let other non-real-time apps from this similar supply have the identical EF priority amount. So, when you're heading to configure your routers to remark all incoming packets for the edges, make sure that you realize what incoming markings are legitimate.
In that situation, the routers are jogging DLSw to bridge SNA page views by means of an IP network. And so the routers their selves in reality design the IP packets. This makes a further problem due to the fact there is no incoming interface. To make sure that recipe usages regional policy-based routing. The actual fact the router creates the packets also provides it a significant advantage on the grounds that it does not have to consider any DLSw packets which may just transpire to go through.
The advantages of the newer class-map approach aren't obvious in this example, but one of several primary great rewards seems if you want to use the greater fashionable DSCP tagging scheme. Since the mature policy-based routing approach isn't going to right support DSCP, you've got to fake it by setting the two the IP Precedence also, the TOS separately 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 may even be helpful later within this chapter after we speak about class-based weighted reasonable queuing and class-based visitors shaping.
It is very important to note that all through this complete instance, now we have only set a amazing value into your packet's TOS or DSCP field. This, by alone, isn't going to affect how the packet is forwarded by way of the network. To undertake that, you ought to be sure that as every single router inside network forwards these marked packets, the interface queues will react appropriately to this information.
At last, we should always observe that as this recipe reveals two invaluable ways of marking packets, working with Committed Entry Rate (Car or truck) elements. Autobus tends to become a little more reliable on higher pace interfaces.
