Riverstone Networks WICT1-12 - Manual (Page 634)

30-30 Riverstone Networks RS Switch Router User Guide Release 8.0
Channelized T1, E1 and T3 Services Overview WAN Configuration
30.16 CHANNELIZED T1, E1 AND T3 SERVICES
OVERVIEW
The Channelized T1 and E1 services are full duplex TDM services that provide aggregation for low speed services that
have different bandwidth requirements, such as voice, data, video, and so on, using one or more 64 kbps (DS0)
channels. The full (unframed) T1 and channelized T3 services, on the other hand, provide a cost effective
Multi-Tenant-Unit/Multi-Dwelling-Unit (MTU/MDU) aggregation solution into a Metropolitan Service Provider
(MSP) hub.
The T1 service is the entire end-to-end service, and runs over the DS1 interface. Similarly, T3 is the service and DS3
the interface. The number of channels, and the capacity of each interface is listed in
Table 30-1 .
30.16.1 T1 and E1 WAN Interface Cards
Each T1 and E1 WAN Interface Card (WIC) has two ports, and an internal CSU/DSU. The T1 WIC has two RJ-48c
connectors, and the E1 WIC has two 120 Ohm RJ-45 connectors. Two T1 or E1 WICs, or a T1 and E1 WIC, can be
installed in a Multi-Rate WAN module, giving a total of four ports. Each T1/E1 WIC has three modes of operation,
depending on the service requirements:
• Channelized T1 and E1, for services that require multiples of 64 kbps bandwidth. A single channel
is used for each service — for example, T1 can have 24 DS0 channels.
• Fractional T1 and E1, for services that require multiples of the 64 kbps channels. For example, T1
services may be high-speed data on a 512 kbps channel, plus 16 low speed data and voice channels
at 64 kbps.
• Full (unstructured) T1 and E1, when a service requires the full T1 or E1 bandwidth. For example,
point-to-point data transmission.
Framing and line coding schemes are employed to ensure the reliable transmission of the data; the schemes used
depend on the interface, as shown in
Table 30-2 .
Table 30-1 Channelized DS1, E1 and DS3 Interfaces
Interface Number of
Channels Capacity
(Mbps) Line Speed
(Mbps)
DS1 24 DS0 channels 1.536 1.544
E1 32 1.920/
1.984 2.048
DS3 28 DS1 lines 43.008 44.736