Determining Appropriate Modular Interfaces

© 2004 Cisco Systems, In

© 2004 Cisco Systems, In

If you select a fixed-configuration router, you receive the router with the interfaces already installed on the box. However, you cannot add or change interfaces on a fixed-configuration router.

Modular routers and access servers such as the Cisco 3600 Series are built with one or more slots that allow you to customize the box. You can determine the types of interfaces on the router by selecting various feature cards, network modules, or WICs to install. Although modular routers require adding equipment to the physical router, they are more scalable as your network grows and your needs change.

Network Cabling and Assembly

This topic describes the cables that are used to connect the network components.

Assembling the Network

Assembling the Network

© 2004 Cisco Systems, Inc. All rights re

© 2004 Cisco Systems, Inc. All rights re

The figure illustrates the cable connections that are available for various WAN types. These include:

1. Asynchronous connections: Asynchronous connections require RJ-11 cables attached from the modem line port to the telephone company jack. If you are using an external modem attached to a Cisco router, you must also use a Cisco EIA/TIA-232 cable to attach the modem to the serial interface of the router. The DB-60 end of the cable connects to the router. The DB-25 end attaches to the modem.

2. ISDN BRI: ISDN BRI connection interfaces require RJ-45 cables to connect the BRI interface to the ISDN network. The BRI modules and BRI WICs are available with either an S or T interface that requires an external NT-1 or a U interface with a built-in NT-1.

3. ISDN PRI (North America): Channelized T1 (CT1)/PRI modules are available with or without a built-in CSU. If you use an external CSU, attach a female DB-15 cable to the interface of the router. The other end of the straight-through cable will attach to the CSU, which in turn attaches to the ISDN network. Routers with internal CSU modules attach directly to the ISDN network with a standard RJ-48 connector.

4. ISDN PRI (Europe): Channelized E1 (CE1)/PRI modules are available with balanced and unbalanced interfaces. CE1/PRI-balanced modules provide a 120-ohm E1 interface for network connections. The unbalanced modules provide a 75-ohm E1 interface for network connections. Four serial cables are available from Cisco for the CE1/PRI module. All four cables have DB-15 connectors on the router end and DNC, DB-15, twinaxial, or RJ-45 connectors on the network end.

5. Frame Relay: If you establish a Frame Relay serial connection, Cisco routers support the following signaling standards: EIA/TIA-232, EIA/TIA-449, V.35, X.21, and EIA-530. Cisco supplies a DB-60 shielded serial transition cable with the appropriate connector for the standard that you specify. The router end of the shielded serial transition cable has a DB-60 connector, which connects to the DB-60 port on the serial interface of the router. The other end of the serial transition cable varies according to the standard that you specify.

6. Broadband: Broadband connections will generally require an Ethernet interface port and service provider equipment. Data service is generally provided through equipment from the provider and converted to RJ-45 by the customer.

Note You can use the RJ-48 and DB-15 cables for Frame Relay connections. They can be plugged into a T1 carrier interface. After a channel group is configured, Frame Relay encapsulation can be run over the connection.

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