Differentiated service (Differentiated services)

Differentiated Services (DIFFSERV) are a technique for achieving quality of service (QoS). Using DiffServ on your network allows you to configure the appropriate parameters directly on switches and routers more easily than using a specific protocol. This chapter describes how to configure the 7000-series network management switch to define what type of traffic the packet belongs to and how such packets should be set to be QoS-appropriate. As a function of the 7000-series Network management switch, DiffServ allows you to control which traffic is received and forwarded, and which traffic should be discarded.

How to set up DiffServ support on a 7000-series switch will vary depending on the role your switch plays in the network: Edge devices: edge devices process incoming traffic, forward traffic to the network core, and forward traffic to the core output. The edge device isolates the inbound traffic into a small set of traffic types, and is responsible for determining a packet rating. The classification is mainly based on the packet header content of the third and fourth layers and the Differentiated service coding Point (DSCP) recorded in the packet IP header. internal nodes: Network core switches are responsible for packet forwarding more than they rank. It decodes the DSCP coding points of incoming packets and provides appropriate queue management algorithms for storage and forwarding services.

Before you make a detailed diffserv configuration of the 7000-series network management switches, you must determine the QoS requirements for this networking. These requirements are represented by the classification rules for inbound traffic defined on a specific interface, and the switch software temporarily does not support the DiffServ of outbound direction.

DiffServ rules are defined according to categories (class), Policies (Policy), and Services (service): class: A classification consists of a set of rules that define the classification of the packet attribution. The inbound flow is classified into traffic according to the third and fourth tier data headers, VLAN numbers and the corresponding DSCP values defined. Supports a Category:all, which specifies that all matching criteria for the classification must match before it takes effect. Policy: defines QoS characteristics for one or more classifications, for example, to mark incoming packets. The 7000 series network management switch supports the traffic situation strategy. This strategy combines the inbound traffic classification to specify the action of the packet when it encounters a matching classification: – A DSCP encoding point, IP priority, or COS tag for the packet. – Develop packet forwarding policies such as discarding or labeling packets that exceed the specified bandwidth of the classification-statistics flow Service in the category : Specifies the policy for the inbound traffic of an interface.

command Line interface example:

This example describes how network administrators can provide equal access (or external network) bandwidth to different parts of a company. All four departments have their own class B address segments and allow 25% of the bandwidth of the Internet port.

Figure 11-1

The following are examples of configuring the 7000-Series Network management switches:

enable the DiffServ feature on the switch. (Netgear switch) #config (Netgear switch) (config) #DiffServ Create DiffServ matching classes for all departments and name them. Define the matching criteria for the new class-the source IP address. (Netgear Switch) (Config) #Class-map match-all finance_dept (Netgear Switch) (Config class-map) #match Srcip 172.16.10.0 255.255.255.0 (Netgear Switch) (Config class-map) #Exit (Netgear Switch) (Config) #Class-map match-all marketing_dept (Netgear Switch) (Config class-map) #match Srcip 172.16.20.0 255.255.255.0 (Netgear Switch) (Config class-map) #Exit (Netgear Switch) (Config) #Class-map match-all test_dept (Netgear Switch) (Config class-map) #match Srcip 172.16.30.0 255.255.255.0 (Netgear Switch) (Config class-map) #exit (Netgear Switch) (Config) #Class-map match-all development_dept (Netgear Switch) (Config class-map) #match Srcip 172.16.40.0 255.255.255.0 (Netgear Switch) (Config class-map) #Exit Create a DiffServ policy named "internet_access" for inbound traffic, adding the class previously created in the example in this strategy. This policy defines different queue attributes for traffic that is outgoing across departments. Here is how to establish the association of DiffServ's pit stop strategy with the Cos queue setting: (Netgear Switch) (Config) #Policy-map internet_access in (Netgear Switch) (Config policy-map) #class Finance_dept (Netgear Switch) (Config policy-class-map) #Assign-queue 1 (Netgear Switch) (Config policy-class-map) #Exit (Netgear Switch) (Config policy-map) #class Marketing_dept (Netgear Switch) (Config policy-class-map) #Assign-queue 2 (Netgear Switch) (Config policy-class-map) #Exit (Netgear Switch) (Config policy-map) #class Test_dept (Netgear Switch) (Config policy-class-map) #Assign-queue 3 (Netgear Switch) (Config policy-class-map) #Exit (Netgear Switch) (Config policy-map) #class Development_dept (Netgear Switch) (Config policy-class-map) #Assign-queue 4 (Netgear Switch) (Config policy-class-map) #Exit (Netgear Switch) (Config policy-map) #Exit apply the defined policy to the inbound direction on the interface 1/0/1 to the 1/0/4. (Netgear Switch) (Config) #interface 1/0/1 (Netgear Switch) (Interface 1/0/1) #Service-policy in internet_access (Netgear Switch) (Interface 1/0/1) #Exit (Netgear Switch) (Config) #interface 1/0/2 (Netgear Switch) (Interface 1/0/2) #Service-policy in internet_access (Netgear Switch) (Interface 1/0/2) #Exit (Netgear Switch) (Config) #interface 1/0/3 (Netgear Switch) (Interface 1/0/3) #Service-policy in internet_access (Netgear Switch) (Interface 1/0/3) #Exit (Netgear Switch) (Config) #interface 1/0/4 (Netgear Switch) (Interface 1/0/4) #Service-policy in internet_access (Netgear Switch) (Interface 1/0/4) #Exit at the (hypothetical) exit interface 1/0/5 The COS queue such as 1,2,3 and 4 sets the minimum guaranteed bandwidth of 25%. All queues on this interface use the default series of most advantageous timing arrangements. The DiffServ Inbound strategy specifies the attributes of these wait queues for each department's traffic, and it assumes that the switch will have the normal destination address as the Internet traffic to the 1/0/5 interface. (Netgear Switch) (Config) #interface 1/0/5 (Netgear Switch) (Interface 1/0/5) #cos-queue min-bandwidth 0 0 0 0 (Netgear Switch) (Interface 1/0/5) #Exit (Netgear Switch) (Config) #Exit

DiffServ Example of setting up VoIP

A valuable DiffServ use is to support ip-based voice (VOIP). VoIP traffic is a fixed time sensor: In a network that provides a service, it is important to ensure the transmission rate. This example shows how to set up one-way to provide the necessary quality of service.

A class of UDP traffic, in the pit direction has done a flow mark, and then in the outbound direction to ensure that the flow of traffic. As with the Router 1 configuration script in Figure 11-2, the same router 2 should also be configured to do the corresponding configuration script.

Figure 11-2

The following example configures DiffServ to support VoIP:

Enter global configuration mode. Set Queue 5 on all ports to use the exact priority mode, which is listed as all VOIP packets. and activates the DiffServ function on the switch. (Netgear Switch) #config (Netgear Switch) (Config) #Cos-queue Strict 5 (Netgear Switch) (Config) #DiffServ Create a DiffServ category named "Class_voip" and define a single matching criterion for the UDP package to be instrumented. The type of this category is "match all" to indicate that all matching criteria must match so that each packet is properly matched. (Netgear Switch) (Config) #Class-map match-all Class_voip (Netgear Switch) (Config class-map) #match protocol UDP (Netgear Switch) (Config class-map) #Exit Create a second DiffServ category named "Class_ef" and define a single matching criterion for packets that detect DiffServ's differentiated service Encoding point (DSCP) for "EF" (expedited forward). It handles incoming traffic that is marked "EF" elsewhere in the network. (Netgear Switch) (Config) #Class-map match-all class_ef (Netgear Switch) (Config class-map) #match IP DSCP EF (Netgear Switch) (Config class-map) #Exit Create a DiffServ policy named "Pol_voip" for inbound traffic, and then add the previously defined category "Class_ef" and "Class_voip" to this policy. This policy handles incoming UDP packets labeled "EF" packets (defined by ' class_ef '), or tagged by ' class_voip ', to mark the DSCP value ' EF '. Matching packets use the Queue 5 internal tag on the outbound port where the data is forwarded. (Netgear Switch) (Config) #Policy-map Pol_voip in (Netgear Switch) (Config policy-map) #class class_ef (Netgear Switch) (Config policy-class-map) #Assign-queue 5 (Netgear Switch) (Config policy-class-map) #Exit (Netgear Switch) (Config policy-map) #class Class_voip (Netgear Switch) (Config policy-class-map) #Mark IP-DSCP EF (Netgear Switch) (Config policy-class-map) #Assign-queue 5 (Netgear Switch) (Config policy-class-map) #Exit (Netgear Switch) (Config policy-map) #Exit apply the defined policy in the port inlet direction. (Netgear Switch) (Config) #interface 1/0/2 (Netgear Switch) (Interface 1/0/2) #Service-policy in Pol_voip (Netgear Switch) (Interface 1/0/2) #Exit (Netgear Switch) (Config) #Exit