Cisco 7940G Посібник адміністратора - Сторінка 3

Переглянути онлайн або завантажити pdf Посібник адміністратора для IP-телефон Cisco 7940G. Cisco 7940G 15 сторінок. Ios telephony services ip phone
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Chapter 1

Product Overview

SIP Clients

SIP clients include:

•

SIP servers include:

•

Cisco SIP IP phones are full-featured telephones that can be plugged directly into an IP network and can

be used very much like a standard private branch exchange (PBX) telephone. The Cisco SIP IP phone is

an IP telephony instrument that can be used in VoIP networks.

The Cisco SIP IP phone model terminals can attach to the existing data network infrastructure, via

10BASE-T/100BASE-T interfaces on an Ethernet switch. When used with a voice-capable Ethernet

switch (one that understands type of service [ToS] bits and can prioritize VoIP traffic), the phones

eliminate the need for a traditional proprietary telephone set and key system and PBX.

The Cisco SIP IP phone complies with RFC 2543.

OL-2206-01

Phones—Can act as either a UAS or UAC. Softphones (PCs that have phone capabilities installed)

and Cisco SIP IP phones can initiate SIP requests and respond to requests.

Gateways—Provide call control. Gateways provide many services, the most common being a

translation function between SIP conferencing endpoints and other terminal types. This function

includes translation between transmission formats and between communications procedures. In

addition, the gateway also translates between audio and video codecs and performs call setup and

clearing on both the LAN side and the switched-circuit network side.

Proxy server—The proxy server is an intermediate device that receives SIP requests from a client

and then forwards the requests on the client's behalf. Basically, proxy servers receive SIP messages

and forward them to the next SIP server in the network. Proxy servers can provide functions such as

authentication, authorization, network access control, routing, reliable request retransmission, and

security.

Redirect server—Receives SIP requests, strips out the address in the request, checks its address

tables for any other addresses that may be mapped to the one in the request, and then returns the

results of the address mapping to the client. Basically, redirect servers provide the client with

information about the next hop or hops that a message should take and then the client contacts the

next hop server or UAS directly.

Registrar server—Processes requests from UACs for registration of their current location. Registrar

servers are often co-located with a redirect or proxy server.

What Is the Cisco SIP IP Phone?

Cisco SIP IP Phone Administrator Guide Version 3.0

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