Introduction

The E1 interface terminates or distributes E1 facility signals for the purpose of processing the SS7 signaling links carried by the E1 carrier. The E1 interface can be either a an E1/T1 MIM card, an E5-E1T1-B card, or SLIC card as shown in Figure A-1, and Figure A-2. The E1/T1 MIM or E5-E1T1-B card can also be used as a T1 interface. This appendix describes how an E1 interface is configured using either the the E1/T1 MIM card or E5-E1T1-B card. The T1 interface configuration is described in T1 Interface.

Note:

The procedures in this appendix are used only to configure E1 signaling links on the E1/T1MIM card or E5-E1T1-B card. To configure an E1 high-speed signaling link (on the LIME1ATM card), go to the Adding an ATM High-Speed Signaling Link procedure.

The E1/T1 MIM card contains up to eight signaling links and allows the EAGLE to contain more than 500 signaling links.

Figure A-1 E1/T1 MIM Block Diagram

Figure A-2 E5-E1T1-B Block Diagram

Table A-1 provides an overview of the functions of the E1 card and the channel card.

Table A-1 Functional Overview of the E1 and Channel Card

Card	Function
E1	Connectivity of both E1 interfaces to a 120 Ohm or 75 Ohm E1 interface. An external adapter is required for the 75 Ohm interface. Processing up to a total of eight (only two if an E1T1 MIM is being used) time slots from the E1 interfaces Interface E1 port 1 through an external backplane to channel cards for processing of additional time slots
Channel	Processing up to eight (only two if an E1T1 MIM configured as a channel card is being used) time slots from the E1 interface Interface through an external backplane to an E1 card to process up to eight (only two if an E1T1 MIM configured as a channel card is being used) time slots

Configured as an E1 Card

Configured as an E1 card, two separate and independent E1 inputs can be terminated on an E1 card. If an E1/T1 MIM is being used, one to eight bi-directional channels are extracted from the E1 inputs and processed as SS7 signaling links. Implemented as E1 Link Interface Modules, up to thirty two separate and independent E1 inputs can be terminated in an Extension Shelf. The E1 card can support signaling links transmitting at either 56 kbps or 64 kbps.

Configured as a Channel Card

In an Extension shelf equipped with an E1 cabling backplane, an E1 card terminates one or two E1 inputs and connects the E1 port 1 input to one of eight available busses on the E1 cabling backplane. Channel cards also connected to the E1 cabling backplane are able to extract any eight signaling channels from the same E1 port 1 input. In this manner, up to 31 E1 channels can be used for signaling - the 32^nd channel is reserved for E1 synchronization. The E1 card can support signaling links transmitting at either 56 kbps or 64 kbps.

Note:

An E5-E1T1-B card cannot be used as a channel card.

High Capacity Multi-Channel Interface Module (HC-MIM) and Eagle 5 - E1 T1 Interface (E5-E1T1)

The EAGLE 5 - E1 T1-B Interface (E5-E1T1-B) provides access to eight E1 ports residing on backplane connectors A and B. Each data stream consists of 31 E1 DS0 signaling links assigned in a time-division multiplex manner. Each channel occupies a unique timeslot in the data stream and can be selected as a local signaling link on the interface card. A maximum of 64 E1 signaling links can be assigned to an appropriate card. A maximum of 32 E1 signaling links can be assigned to an E5-E1T1-B card.

To support the processing of signaling channels that are intermixed on trunks with voice or data channels, the E5-E1T1-B card allows E1 ports to be channel bridged. This allows better utilization of E1 bandwidth without dedicating entire trunks to signaling.

Figure A-3 Channel Bridging

Channel bridging is implemented by pairing odd and even E1 ports. The E1 port selected for channel bridging is the odd numbered port (1, 3, 5, 7). When the E1 port is selected for channel bridging, it is paired with its adjacent even numbered port (2, 4, 6, 8) as shown in Table A-2.

Table A-2 Channel Bridging E1 Port Pairing

Odd Numbered E1 Port (Bridging Master)	Even Numbered E1 Port Bridged to the Odd Numbered E1 Port (Bridging Slave)
1	2
3	4
5	6
7	8

By pairing E1 ports, the adjacent even numbered E1 port could be used to allow data received on the bridging master (odd) E1 port to reach downstream network elements. This interface is a bi-directional interface so data is also able to enter the bridging slave (even) E1 port and leave the EAGLE through the bridging master (odd) E1 port. There is a 1 to 1 correspondence between the timeslots on the bridging master and slave E1 ports.

In order to use channel bridging without facility errors, both E1 ports (bridging master and slave) must be synchronous (timed off the same clock source). This may be accomplished in one of the following ways:

• The bridging master E1 port and the bridging slave E1 port use timing recovered from each other (using the e1tsel=recovered parameter with either the ent-e1 or chg-e1 command). When provisioning channel bridged E1 port, only the bridging master E1 port is provisioned with the ent-e1 or chg-e1 command. The bridging slave E1 port is automatically provisioned with the same attributes as the bridging master E1 port.
• Both the bridging master and slave E1 ports are using an external clock source (using the e1tsel=external parameter when provisioning the channel bridged E1 port with either the ent-e1 or chg-e1 command).

Any other methods used for timing could cause problems on the E1 trunk and are not supported.

Idle patterns on the shadow channels, that is, the timeslots located on the bridging slave E1 port that have been not been dropped from the bridging master E1 port, are provided by the EAGLE. All other idle timeslots that are not dropped by the EAGLE must contain an idle pattern provided by the remote network elements connected to both E1 ports (bridging master and slave). Without these patterns on the idle timeslots, instability of the E1 signaling link may occur.

Provisioning of signaling links on the bridging slave E1 port is not allowed while the bridging master E1 port is channel bridged.