Cisco Systems ATA187I1ARF Secure Real-Time Transport Protocol, Transport Layer Security Protocol

Chapter 1 Cisco ATA 187 Analog Telephone Adaptor Overview

Software Features

Secure Real-Time Transport Protocol

Secure Real-Time Transport Protocol secures voice conversations on the network and provides protection against replay attacks.

Name Signaling Event based passthrough

Name Signaling Event (NSE)-based passthrough is simply thet transport of fax or modem communications using the G.711 codec.

The ATA 187 does not support NSE-based modem passthrough.

Transport Layer Security Protocol

Transport Layer Security (TLS) is a cryptographic protocol that secures data communications such as e-mail on the Internet. TLS is functionally equivalent to Secure Sockets Layer (SSL).

T.38 Fax Relay

The T.38 fax relay feature enables devices to use fax machines to send files over the IP network. In general, when a fax is received, it is converted to an image, sent to the T.38 fax device, and converted back to an analog fax signal. T.38 fax relays configured with voice gateways decode or demodulate the fax signals before they are transported over IP. With the SIP call control protocol, the T.38 fax relay is indicated by Security Description (SDP) entries in the initial SIP INVITE message. After the initial SIP INVITE message, the call is established to switch from voice mode to T.38 mode. Cisco Unified Communications Administration allows you to configure a SIP profile that supports T.38 fax communication.

Voice Codecs Supported

The ATA 187 supports these voice codecs (check your other network devices for the codecs they support):

•G.711µ-law

•G.711A-law

•G.729A

•G.729B

•G.729AB

Other Supported Protocols

The ATA 187 supports these additional protocols:

•802.1Q VLAN tagging

•Cisco Discovery Protocol (CDP)

Cisco ATA 187 Analog Telephone Adaptor Administration Guide for SIP (Version 1.0)

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