Determining the Configuration

External Interface Descriptions

The E1 Interface Backplane provides a method for extending individual E1 channels from the E1-configured cards to any channel-configured cards in use. Note the following issues regarding the E1 backplane:

• Only one E1-configured card may be plugged into each bus on the backplane.

• When installing non-E1 cards on the shelf equipped with the E1 interface backplane, ensure that none of the slots to be used are cabled to the E1 interface backplane. If a non-E1 card is installed in a slot that is connected to the E1 backplane, all E1 cards on that bus may fail.

• Only one E1 card may be connected (via the B port) to each bus of the E1 cabling backplane, and all SS7 links derived from any particular E1 must be processed on the same shelf on which the incoming E1 is terminated.

• Due to cable congestion, Oracle does not recommend use of the E1 cabling backplane on the control shelf.

• If the control shelf is used, a maximum of 20 E1 interfaces can be utilized in the control shelf.

The E1 backplane is impedance-controlled for 120 Ohms and is designed for use with RS-485 transmission characteristics.

Descriptions of the T1 hardware and the procedures for installing the T1 hardware are contained in Hardware Reference and Installation Guide.

Possible Configurations

The E1 backplane was designed to allow the maximum number of possible customer setups. It allows the customer to choose between several levels of diversity and convenience. Configurations depend on the number of cards configured as E1 cards versus the number of cards configured as channel cards. The level of diversity required by the customer also affects the configuration requirements. Note that all signals labelled “E1 input” may be one or two E1 ports depending on the cable used.

Support of Two E1 Ports

The E1 card will support two E1 ports, which are independently configurable. On an E1 card, E1 port 1 will support channel cards. The second port of that E1 card will only support up to a maximum of eight time slots and will not support channel cards.

Clocking Options

Each E1 interface must independently operate in one of two clocking modes. When configured as a channel card, an E1 card is required for the channel card’s clocking source.

• Slave Timing - The default receive clock on the E1 card will be used as the source of the transmit clock.

• Master Timing - The transmit clock of the E1 card will originate on this board. The oscillator on the board provides the clock source. Note the oscillator is less accurate than the network clock.

The Master Timing feature allows an E1 signaling link to take its high-speed clock reference directly from an external high-speed master clock source.

Support of E1 Framing Options

The E1 interfaces will independently support the following E1 framing options. Selection of these options will be made by the crc4 and cas parameters of either the ent-e1 or chg-e1 commands.

• Clear Channel Signaling (CCS)

• Channel Associated Signaling (CAS)

• Cyclic Redundancy Check (CRC4)

The following provide for zero bit suppression: HDB3 (High Density Bipolar encoding of order 3).

On any given E1 card, CCS and CAS are mutually exclusive and cannot be used together. However, CRC4 may be added to either CCS or CAS.

LIM-E1 Card to Channel Card Interface

Whether the E1/channel card is operating as an E1 card or a channel card, the card will map any eight channels from the E1 interfaces to an HDLC controller (ports A, B, A1, B1, A2, B2, A3, B3 for the E1/T1 MIM card). These channels could be dropped either both from E1 port 1 or one from E1 port 1 and the other from E1 port 2. When the E1/channel card is configured as an E1 card, it will support the external E1 cabling backplane interface from E1 port 1 (E1 port 2 will not have this capability) to additional E1/channel cards, within the same shelf, configured as channel cards. Idle time slots not assigned to an E1 card or a channel card will be filled with a one’s pattern.

Channel Support

The E1/channel card will independently support either 56 kbps or 64 kbps on any channel.

Configuring the Signaling Links

The main consideration for the provisioning of E1s is to determine the number of E1s existing in the network and the equipment needed for grooming into the EAGLE. To utilize the flexibility of the E1 interface feature, you may want to determine the minimum number of E1 cards needed to process the total number of SS7 links and then consider diversity for reliability reasons.

Use the following points as guidelines when considering diversity for E1:

• If possible, no two E1s containing links from a common link set should be on the same E1/dual port channel card.

• If possible, no two E1s containing links from a common link set should be on adjacent E1/dual port channel cards where they are powered from the same fuse position.

• If possible, no two E1s containing links from a common link set should be terminated on the same shelf because of the shelf clock cabling, and is only an issue if using master clocking sync to the network

• If possible, no two links in a link set should arrive at the EAGLE on the same E1.

• If possible, for link sets containing more than two links, you should minimize the number of links in that link set on any given E1.

As an example, consider a network to be groomed into the EAGLE consisting of 30 E1s with a total number of 100 links where the largest link set size is 8. The most efficient way to provision the EAGLE would be to have four extension shelves equipped with the E1 cabling backplane, one E1 card, and 12 channel cards per shelf. Utilizing one B bus on each shelf, 25 signaling links would be terminated on each shelf for a total of 100. This is also the minimum number of E1 cards required for this example.

With the same example but using the third and fifth bullets above as a consideration, the EAGLE would be provisioned with eight extension shelves equipped with the E1 cabling backplane. Four of the shelves would be equipped with one E1 card and six channel cards, and the other four shelves would be equipped with one E1 card and five channel cards. Since the largest link set size is eight, a total of eight E1 cards is required. Utilizing one B bus on each shelf, 13 signaling links would be terminated on each shelf with six channel cards, and 12 signaling links would be terminated on each shelf with five channel cards.

Note:

When retrieving link information from the database, the links for an E1 or channel card is not displayed until after the card is allowed.

E1 Configuration Form

Use the form provided below to record your E1 configuration. An example of the required input is shown in italics under each column heading.

Table A-3 E1 Signaling Link Configuration Form

Card Location and Port (1201 A)	Timeslot (1)	E1 Number (1)	E1 Card Location (1201)	Adjacent Point Code (4001)	Linkset ( ST1ME )	SLC (1)