Cisco Systems RJ-45-to-AUX manual 377

support CDP.

Cisco Express Forwarding (CEF)

Used in the CEF ASIC (CEFA) and Distributed Cisco Express Forwarding (dCEF) ASIC, Cisco’s newest ASICs. These ASICs, which are used in Cisco’s high−end devices, are the most functional and efficient ASICs in the Cisco product line. They use a CEF search engine, which makes IP prefix−based switching decisions using an adjacency table. The CEFA operates at both Layer 2 and Layer 3, using ARP to resolve next−hop adjacencies at Layer 2. A network interface is said to be adjacent if it can be reached in a single hop. This component looks at the first 64 bytes of an incoming frame, obtains as much information as possible, and then uses the switch’s CAM table to rewrite the relevant source MAC address, destination MAC address, or destination network address to the frame or packet header.

Cisco Group Management Protocol (CGMP)

A Cisco protocol used by the Catalyst switch to forward multicast frames intelligently. CGMP dynamically discovers end−user stations participating in multicast applications. When receiving a multicast, it forwards the multicast directly to the end users instead of broadcasting the multicast throughout the network.

Class A network

A TCP/IP network that uses addresses starting between 1 and 126 and supports up to 126 networks with up to 16,777,214 unique hosts each. 127 is a Class A address but is used for loopback testing on Ethernet interfaces.

Class B network

A TCP/IP network that uses addresses starting between 128 and 191 and supports up to 16,384 networks with 65,534 unique hosts each.

Class C network

A TCP/IP network that uses addresses starting between 192 and 254 and supports up to 2,097,152 networks with 254 unique hosts each.

Classless Inter−Domain Routing (CIDR)

A technique that allows multiple addresses to be consolidated into a single entry. Clear Header

A field (part of the 802.10 header) that copies the encrypted Protected Header for security purposes to help guarantee against tampering with the frame. Also known as the Secure Data Exchange (SDE) Protocol Data Unit.

ClearChannel Architecture

The switching architecture found in the Cisco Catalyst series 1900 and 2820 switches. The architecture is made up of the 1Gbps Packet Exchange Bus, Forwarding Engine, Embedded Control Unit, a management interface, and a 3MB shared memory buffer.

client

A node that requests a service from another node on a network. client/server networking

A networking architecture utilizing front−end demand nodes that request and process data stored by the back end or resource node.

coaxial cable

Data cable, commonly referred to as coax, made of a solid copper core, which is insulated and surrounded by braided metal and covered with a thick plastic or rubber covering. This is the standard cable used in cable TV and in older bus topology networks.

collapsed core

A design in which both the Core and Distribution layers’ functions are combined into one layer. collision

The result of two frames transmitting simultaneously in an Ethernet network and colliding, thereby destroying both frames.

collision domain

All the interfaces on a single segment that can send data on the same physical wire. In the case of a switch, all the nodes connected to each individual port are in their own collision domain. In a hub, all the interfaces connected to the hub ports are in their own collision domain.

Color Blocking Logic (CBL)

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