In this lab, you will configure two routers to act as H.323 gateways and one router to act as an H.323 gatekeeper. Routers R1 and R3, which are illustrated in Figure 6-53, will each act as H.323 gateways in different zones. Router R2 will serve as an H.323 gatekeeper and restrict call bandwidth usage between these zones to a total of 64 and limit per-call bandwidth to 16 kbps.
The per-call bandwidth limit of 16 kbps accommodates a single G.729 call. The gatekeeper does not measure the actual bandwidth used per call. Rather, the gatekeeper assumes the required bandwidth for a call is double the bandwidth required for the payload of the call. In this example, a call using the G.729 CODEC requires 8 kbps of bandwidth for the voice payload, not including overhead. Therefore, the H.323 gatekeeper assumes the required bandwidth for the call is double that amount (that is, 16 kbps).
In this task, you will configure router R2 as an H.323 gatekeeper.
Complete these steps:
In this task, you will configure routers R1 and R2 as H.323 gateways that register with the gatekeeper you configured in Task 1.
Complete these steps:
1. | Enable H.323 gateway processing on router R1 with the gateway command in global configuration mode. |
2. | Go into interface configuration mode for the R1 interface that connects R1 to R2 and indicate that the interface is an H.323 interface using the h323-gateway voip interface command. |
3. | Still in interface configuration mode, tell router R1 to register with the gatekeeper you created in Task 1 using the h323-gateway voip id ZoneA ipaddr 10.7.7.1 1719 command. This command causes router R1 to register as an H.323 gateway in Zone A using the gatekeeper’s RAS address of 10.7.7.1 and using the default port number of 1719. |
4. | |
5. | Enter the command h323-gateway voip tech-prefix 1# to tell router R1 to register with the gatekeeper using the gatekeeper’s default technology prefix of 1#. |
6. | In the lab at the end of Chapter 4, “Voice Dial Peer Configuration,” you configured a VoIP dial peer on router R1 that pointed to a phone number of 2222 by sending VoIP packets to an IP address of 10.7.7.2. Enter dial peer configuration mode for this dial peer and remove the previous session target with the no session target ipv4:10.7.7.2 command. Then add a new session target pointing this dial peer to the gatekeeper, using the session target ras command. This command instructs this H.323 gateway to use the RAS channel to send a call setup request to the interface’s gatekeeper when attempting to place a call to a dial string of 2222. |
7. | Now that you have successfully configured router R1, next create a mirrored configuration for router R3. Adapt the commands given in Steps 1–6 for router R3, such as specifying a zone name of Zone B and an H.323 ID of R3. Also, the VoIP dial peer you modify on router R3 will be the VoIP dial peer that points to a dial string of 1111. |
In this task, you will verify the configuration of the H.323 gatekeeper and the two H.323 gateways.
Complete these steps:
Step 1. | The first indication that your configuration is correct is the ability to successfully place a phone call between extensions 1111 and 2222. Therefore, from extension 1111, attempt to place a phone call to extension 2222. If the call is successful, leave the handsets off-hook while performing the following steps. If, however, the call does not complete successfully, work back through each step of the lab, carefully examining the configurations of the routers. |
Step 2. | With a call successfully in progress, issue the show gateway command on routers R1 and R3 to verify that these gateways have registered with the gatekeeper. |
Step 3. | You can also see what H.323 gateways have registered with the gatekeeper by issuing the show gatekeeper endpoints command from router R2. |
Step 4. | To see the types of RAS messages (for example, admission request [ARQ] and admission confirmation [ACF] messages) sent and received by a gateway, you can issue the show h323 gateway ras command. Issue this command on router R1 and notice the ARQ and the ACF representing the call you were permitted to make. |
Although your physical hardware might differ, and your selection of dial peer tags might vary, Examples 6-15 through 6-20 offer possible solutions to the preceding exercise.
Example 6-15 shows the configuration for R2’s H.323 gatekeeper.
gatekeeper zone local ZoneA acme.com 10.7.7.1 zone local ZoneB acme.com zone prefix ZoneA 1... zone prefix ZoneB 2... gw-type-prefix 1#* default-technology arq reject-unknown-prefix bandwidth interzone default 64 bandwidth session default 16 no shutdown |
Example 6-16 shows the configuration for R1’s H.323 gateway.
interface Serial0 bandwidth 128 ip address 10.1.1.2 255.255.255.0 encapsulation ppp h323-gateway voip interface h323-gateway voip id ZoneA ipaddr 10.7.7.1 1719 h323-gateway voip h323-id R1 h323-gateway voip tech-prefix 1# ! gateway ! dial-peer voice 2222 voip destination-pattern 2222 session target ras |
Example 6-17 shows the configuration for R3’s H.323 gateway.
interface Serial0 bandwidth 2000 ip address 10.7.7.2 255.255.255.0 encapsulation ppp clock rate 2000000 h323-gateway voip interface h323-gateway voip id ZoneB ipaddr 10.7.7.1 1719 h323-gateway voip h323-id R3 interface Serial0 h323-gateway voip tech-prefix 1# ! gateway ! dial-peer voice 1111 voip destination-pattern 1111 session target ras |
Example 6-18 shows the output of the show gateway command on R1.
R1#show gateway
H.323 ITU-T Version: 4.0 H323 Stack Version: 0.1
H.323 service is up
Gateway R1 is registered to Gatekeeper ZoneA
Alias list (CLI configured)
E164-ID 1111
H323-ID R1
Alias list (last RCF)
E164-ID 1111
H323-ID R1
H323 resource thresholding is Disabled
|
Example 6-19 shows the output of the show gateway command on R3.
R3#show gateway
H.323 ITU-T Version: 4.0 H323 Stack Version: 0.1
H.323 service is up
Gateway R3 is registered to Gatekeeper ZoneB
Alias list (CLI configured)
E164-ID 2222
H323-ID R3
Alias list (last RCF)
E164-ID 2222
H323-ID R3
H323 resource thresholding is Disabled
|
Example 6-20 shows the output of the show gatekeeper endpoints command on R2.
R2#show gatekeeper endpoints
GATEKEEPER ENDPOINT REGISTRATION
================================
CallSignalAddr Port RASSignalAddr Port Zone Name Type Flags
--------------- ----- -------------- ----- --------- ---- -----
10.1.1.2 1720 10.1.1.2 52605 ZoneA VOIP-GW
E164-ID: 1111
H323-ID: R1
Voice Capacity Max.= Avail.= Current.= 1
10.7.7.2 1720 10.7.7.2 52354 ZoneB VOIP-GW
E164-ID: 2222
H323-ID: R3
Voice Capacity Max.= Avail.= Current.= 1
Total number of active registrations = 2
|
Example 6-21 shows the output of the show h323 gateway ras command on R1.
R1#show h323 gateway ras RAS STATISTICS AT 00:25:56 RAS MESSAGE REQUESTS SENT CONFIRMS RCVD REJECTS RCVD GK Discovery grq 5 gcf 1 grj 0 Registration rrq 34 rcf 34 rrj 0 Admission arq 1 acf 1 arj 0 Bandwidth brq 0 bcf 0 brj 0 Disengage drq 0 dcf 0 drj 0 Unregister urq 0 ucf 0 urj 0 Resource Avail rai 0 rac 0 Req In Progress rip 0 |