Lab Objective:
The focus of this lab is to understand WAN IP Quality of Service(QoS) implementation and configuration. Additional technologies Network-based Application Recognition (NBAR).
Lab Topology:
The lab network topology is illustrated below:
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IMPORTANT NOTE If you are using the www.howtonetwork.net racks, please bring up the LAN interfaces connected to the routers by issuing the no shutdown command on the connected switches. If you are using a home lab with no interface fastethernet 0/0 Alternately, you can simply connect the interfaces to a hub or switch if you have one available in your own lab. |
Task 1
Configure hostnames, IP addressing on all routers as illustrated in the network topology.
Task 2
Configure EIGRP using Autonomous System number 254 as illustrated in the topology. Verify your configuration using the appropriate commands.
Task 3
Assuming that the QoS has been correctly implemented on the LAN subnets connected to R1 and R4, enable the Auto QoS feature on these routers such that they trust the DSCP values of VoIP packets. These WAN links have a bandwidth of 256Kbps. Verify your Auto QoS configuration using the appropriate commands.
Task 4
Management has requested that Auto QoS be enabled on the R2-R3 link. They are concerned that there may be some transit traffic that has not been properly classified and therefore requested that the routers be configured to match VoIP packets using NBAR. Implement this configuration and verify your solution using the appropriate commands.
Task 5
In the future, there will be video traffic traversing the R2-R3 link. Management has requested that this traffic be assigned 30% of the bandwidth. The voice traffic should be using 40% of the bandwidth instead of the current specified value. Modify the QoS policy applied to the LAN interfaces of R2 and R3 to do this. Verify your configuration using the appropriate commands.
Lab Validation
Task 1
Please refer to previous labs for basic IPv4, IPv6 addressing and hostname configuration. This will not be included in this section to avoid being redundant.
Task 2
Please refer to previous labs for basic EIGRP configuration. Following this, verify your EIGRP configuration using the show ip eigrp neighbors andshow ip route commands. Following this configuration, your route tables should show the following route information:
| R1#show ip route eigrp 10.0.0.0/30 is subnetted, 2 subnets D 10.0.0.12 [90/21026560] via 10.0.0.2, 00:00:07, Serial0/0 150.2.0.0/24 is subnetted, 1 subnets D 150.2.2.0 [90/2172416] via 10.0.0.2, 00:01:37, Serial0/0 150.4.0.0/24 is subnetted, 1 subnets D 150.4.4.0 [90/21029120] via 10.0.0.2, 00:00:07, Serial0/0 |
| R2#show ip route eigrp 10.0.0.0/30 is subnetted, 2 subnets D 10.0.0.12 [90/20514560] via 150.2.2.3, 00:00:13, FastEthernet0/0 150.1.0.0/24 is subnetted, 1 subnets D 150.1.1.0 [90/2172416] via 10.0.0.1, 00:01:43, Serial0/0 150.4.0.0/24 is subnetted, 1 subnets D 150.4.4.0 [90/20517120] via 150.2.2.3, 00:00:13, FastEthernet0/0 |
| R3#show ip route eigrp 10.0.0.0/30 is subnetted, 2 subnets D 10.0.0.0 [90/2172416] via 150.2.2.2, 00:00:29, FastEthernet0/0 150.1.0.0/24 is subnetted, 1 subnets D 150.1.1.0 [90/2174976] via 150.2.2.2, 00:00:29, FastEthernet0/0 150.4.0.0/24 is subnetted, 1 subnets D 150.4.4.0 [90/20514560] via 10.0.0.14, 00:00:45, Serial1/2 |
| R4#show ip route eigrp 10.0.0.0/30 is subnetted, 2 subnets D 10.0.0.0 [90/2684416] via 10.0.0.13, 00:00:33, Serial0/0 150.1.0.0/24 is subnetted, 1 subnets D 150.1.1.0 [90/2686976] via 10.0.0.13, 00:00:33, Serial0/0 150.2.0.0/24 is subnetted, 1 subnets D 150.2.2.0 [90/2172416] via 10.0.0.13, 00:00:49, Serial0/0 |
Task 3
The core requirement of this task is straightforward. There caveat however, is that the Auto QoS feature must be enabled on both ends of the link. Therefore, the same configuration will be required on the WAN interfaces of R2 and R3 that are connected to R1 and R4, respectively. The task is therefore completed on all four routers as follows:
| R1(config)#ip cef R1(config)#interface serial 0/0 R1(config-if)#bandwidth 256 R1(config-if)#auto qos voip trust R1(config-if)#exit |
| R2(config)#ip cef R2(config)#interface serial 0/0 R2(config-if)#bandwidth 256 R2(config-if)#auto qos voip trust R2(config-if)#exit |
| R3(config)#ip cef R3(config)#interface serial 1/2 R3(config-if)#bandwidth 256 R3(config-if)#auto qos voip trust R3(config-if)#exit |
| R4(config)#ip cef R4(config)#interface serial 0/0 R4(config-if)#bandwidth 256 R4(config-if)#auto qos voip trust R4(config-if)#exit |
When enabling the Cisco IOS Auto QoS feature, it is important to remember that the bandwidth of the Serial interface determines the speed of the link and the speed of the link in turn determines the configurations generated by the AutoQoS feature. By default, all links with a bandwidth value of 768Kbps and below are considered low bandwidth links. When Auto QoS is enabled on these interfaces, the router converts the link to a PPP Multilink configuration, allowing for better utilization of bandwidth. However, if the link speed is above 768Kbps, then the Auto QoS feature does not use PPP Multilink. Instead, the configuration is implemented for high bandwidth links, i.e. no Multilink interface is created on the router.
Next, verify the applied Auto QoS configuration using the show auto qos command:
| R1#show auto qos ! policy-map AutoQoS-Policy-Trust class AutoQoS-VoIP-RTP-Trust priority percent 70 class AutoQoS-VoIP-Control-Trust bandwidth percent 5 class class-default fair-queue ! class-map match-any AutoQoS-VoIP-RTP-Trust match ip dscp ef ! class-map match-any AutoQoS-VoIP-Control-Trust match ip dscp cs3 match ip dscp af31 ! rmon event 33333 log trap AutoQoS description “AutoQoS SNMP traps for Voice Drops” owner AutoQoS rmon alarm 33335 cbQosCMDropBitRate.1175.1177 30 absolute rising-threshold 1 33333 falling-threshold 0 owner AutoQoS Serial0/0 – |
To view statistics for Auto QoS, use the show policy-map interface command:
| R1#show policy-map interface multilink 2001100115 Multilink2001100115 Service-policy output: AutoQoS-Policy-Trust Class-map: AutoQoS-VoIP-RTP-Trust (match-any) Class-map: AutoQoS-VoIP-Control-Trust (match-any) Class-map: class-default (match-any) |
Task 4
Prior to configuring the Auto QoS Feature, ensure that you are familiar with the following prerequisites and restrictions:
- Cisco Express Forwarding (CEF) is required and must be globally enabled on the router
- Remove any policy-maps currently applied to the interface
- Ensure that the correct bandwidth has been configured for the interface
- Ensure that the interface is configured with an IP address
- The auto qos voip command is not supported on subinterfaces or gigabit interfaces
- The auto qos voip command is supported with Frame Relay DLCIs
- If the trust is not specified, a policy-map named AutoQoS-Policy-UnTrust is created
- If the trust keyword is used, a policy-map named AutoQoS-Policy-Trust is created
Because the Auto QoS for VoIP feature is supported for FastEthernet interfaces, this task is completed by issuing the following commands on R2 and R3:
| R2(config)#interface fastethernet 0/0 R2(config-if)#auto qos voip R2(config-if)#exit |
| R3(config)#interface fastethernet 0/0 R3(config-if)#auto qos voip R3(config-if)#exit |
Next, verify your configuration using the show auto qos command:
| R2#show auto qos ! policy-map AutoQoS-Policy-UnTrust class AutoQoS-VoIP-RTP-UnTrust priority percent 70 set dscp ef class AutoQoS-VoIP-Control-UnTrust bandwidth percent 5 set dscp af31 class AutoQoS-VoIP-Remark set dscp default class class-default fair-queue ! policy-map AutoQoS-Policy-Trust class AutoQoS-VoIP-RTP-Trust priority percent 70 class AutoQoS-VoIP-Control-Trust bandwidth percent 5 class class-default fair-queue ! class-map match-any AutoQoS-VoIP-Remark match ip dscp ef match ip dscp cs3 match ip dscp af31 ! class-map match-any AutoQoS-VoIP-RTP-Trust match ip dscp ef ! class-map match-any AutoQoS-VoIP-Control-Trust match ip dscp cs3 match ip dscp af31 ! class-map match-any AutoQoS-VoIP-Control-UnTrust match access-group name AutoQoS-VoIP-Control ! class-map match-any AutoQoS-VoIP-RTP-UnTrust match protocol rtp audio match access-group name AutoQoS-VoIP-RTCP ! ip access-list extended AutoQoS-VoIP-RTCP permit udp any any range 16384 32767 ! ip access-list extended AutoQoS-VoIP-Control permit tcp any any eq 1720 permit tcp any any range 11000 11999 permit udp any any eq 2427 permit tcp any any eq 2428 permit tcp any any range 2000 2002 permit udp any any eq 1719 permit udp any any eq 5060 ! rmon event 33333 log trap AutoQoS description “AutoQoS SNMP traps for Voice Drops” owner AutoQoS rmon alarm 33334 cbQosCMDropBitRate.1117.1119 30 absolute rising-threshold 1 33333 falling-threshold 0 owner AutoQoS rmon alarm 33335 cbQosCMDropBitRate.1197.1199 30 absolute rising-threshold 1 33333 falling-threshold 0 owner AutoQoS FastEthernet0/0 – Serial0/0 – |
To view statistics for Auto QoS, use the show policy-map interface command:
| R2#show policy-map interface fastethernet 0/0 FastEthernet0/0 Service-policy output: AutoQoS-Policy-UnTrust Class-map: AutoQoS-VoIP-RTP-UnTrust (match-any) Class-map: AutoQoS-VoIP-Control-UnTrust (match-any) Class-map: AutoQoS-VoIP-Remark (match-any) Class-map: class-default (match-any) |
Task 5
This task requires that you create a class map that matches IP video traffic, i.e. RTP Video, and then include it in the existing policy-map applied to the FastEthernet interfaces of routers R2 and R3. Within policy-map configuration mode, you also need to modify the default bandwidth that is assigned to VoIP traffic. This task is therefore completed as follows:
| R2(config)#class-map Untrusted-Video R2(config-cmap)#match protocol rtp video R2(config-cmap)#exit R2(config)#policy-map AutoQoS-Policy-UnTrust R2(config-pmap)#class AutoQoS-VoIP-RTP-UnTrust R2(config-pmap-c)#priority percent 40 R2(config-pmap-c)#exit R2(config-pmap)#class Untrusted-Video R2(config-pmap-c)#bandwidth percent 30 R2(config-pmap-c)#exit |
| R3(config)#class-map Untrusted-Video R3(config-cmap)#match protocol rtp video R3(config-cmap)#exit R3(config)#policy-map AutoQoS-Policy-UnTrust R3(config-pmap)#class AutoQoS-VoIP-RTP-UnTrust R3(config-pmap-c)#priority percent 40 R3(config-pmap-c)#exit R3(config-pmap)#class Untrusted-Video R3(config-pmap-c)#bandwidth percent 30 R3(config-pmap-c)#exit |
Verify your configuration using the show policy-map interface command:
| R2#show policy-map interface fastethernet 0/0 FastEthernet0/0 Service-policy output: AutoQoS-Policy-UnTrust Class-map: AutoQoS-VoIP-RTP-UnTrust (match-any) Class-map: AutoQoS-VoIP-Control-UnTrust (match-any) Class-map: AutoQoS-VoIP-Remark (match-any) Class-map: Untrusted-Video (match-all) Class-map: class-default (match-any) |
Final Router Configurations
R1
| R1#term len 0 R1#sh run Building configuration… Current configuration : 1829 bytes R1# |
R2
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R2#term len 0 Current configuration : 2544 bytes R2# |
R3
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R3#term len 0 Current configuration : 3344 bytes R3# |
R4
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R4#term len 0 Current configuration : 1810 bytes R4# |