CUCM呼叫路由(第7部分):路由列表

我们已经讨论了路由模式、路由组、网关和中继，现在让我们继续讨论路由列表。这些配置元素的逻辑处理顺序如下:路由模式—>路由列表—>路由组—>网关/中继呼叫路由配置的配置顺序必须是自下而上的。如果我们构建了一个路由组，但是没有网关或中继可以放到路由组中，路由组就没有值。如果我们建立了一个路由列表，但是我们没有任何路由组来将路由列表指向…但是，首先让我们介绍一些基础知识，它们将帮助我们描绘出我们希望通过调用路由元素实现的愿景。在分布式呼叫处理环境中，如果有多个思科统一通信管理器(Cisco Unified Communications manager, CUCM)集群，通常会有多条路径在站点之间路由呼叫。呼叫路由的第一选择通常是通过IP广域网进行语音呼叫，从而减少任何PSTN长途费用。这种类型的呼叫路由通常被称为长途旁路，因为我们绕过了在PSTN上放置通信所需的长途收费。这种型号是用来节省国际长途费用的。如果IP WAN无法进行呼叫路由，则需要通过PSTN重新路由该呼叫。 Most deployments use an abbreviated dial plan for inter-site call routing. The number of digits that the dial plan can be abbreviated to is usually dependent on the size of the company and the direct inward dialing (DID) range used at each site. We will investigate an environment with two sites, each with a CUCM cluster. Each site will have a five digit internal dial plan and a seven digit inter-site dial plan. Site 1 will be located in New York City (NYC) and Site 2 will be located in San Jose, California (SJC). The DID range of phone numbers purchased for NYC is (212) 551-XXXX and the DID range for SJC is (408) 622-XXXX. In designing the inter-site dial plan, it was determined that the company could use a five digit inter-site dial plan, but they have planned the dial plan with the expectation of growth in the company. The SJC site will have a route pattern of 55.1XXXX pointed to the NYC Route List named NYC_RL. The NYC site will have a route pattern of 62.2XXXX pointed to the SJC Route List named SJC_RL. A Route List is a logical processing order of one or more Route Groups. The Route Lists mentioned above will each have two Route Groups. The first Route Group will route calls to an H.323 Gatekeeper over the IP WAN. The Gatekeeper will perform the important task of e.164 to IPv4 address translation and Call Admission Control (CAC). The CUCM server has no insight into the bandwidth available over the IP WAN. The network team in this deployment sized the Priority Queue (PQ) QoS mechanism to accommodate 50 G.729 calls. Without a CAC mechanism, CUCM could potentially route thousands of phone calls over this WAN link because CUCM believes that bandwidth is infinite. The H.323 gatekeeper will reject any calls over 50 phone calls so CUCM can re-route the call to the second Route Group pointed to gateways that will deliver the phone calls to the PSTN network. In the next blog, we will explore the digit manipulation techniques employed at the Route List level to ensure only 5 digits are passed over the IP WAN links, while a full 11-digit long distance number is delivered to the PSTN over our gateway interfaces.