Cisco ASR 900 Series Configuration Manual page 5

Cisco Discovery Protocol Version 2 provides more intelligent, device-tracking features than those available in Version 1. One of the
features available is an enhanced reporting mechanism for more rapid error tracking, which helps to reduce network downtime. Errors
reported include mismatched native VLAN IDs (IEEE 802.1Q) on connected ports and mismatched port-duplex states between
connected devices. Messages about reported errors can be sent to the console or to a logging server.
You can use show commands for getting detailed output on VTP management domains and duplex modes of neighboring devices,
counters related to Cisco Discovery Protocol, and VLAN IDs of connecting ports.
When one interface is configured or PPP is configured alone then the CDP configuration is removed with
Note
the removal of configuration of interface or PPP and the CDP process is disabled. In case, if there are two
interfaces configured and configuration of one is removed then the CDP configuration is retained with
that interface.
Using Cisco Discovery Protocol with SNMP
Using Cisco Discovery Protocol with Simple Network Management Protocol (SNMP) allows network management applications to
learn the type of device and the SNMP agent address of neighboring devices. Applications can also send SNMP queries to these
neighboring devices.
The SNMP management application learns protocol addresses and types of neighboring devices by retrieving the Cisco Discovery
Protocol tables from SNMP agents on those devices. When enabled, the network management module (NMM) SNMP agent discovers
neighboring devices and builds its local cache with information about these devices. A management workstation can retrieve this
cache by sending SNMP requests to access CISCO-CDP-MIB.
Cisco Discovery Protocol and On-Demand Routing Support for ATM PVCs
Cisco Discovery Protocol and On-Demand Routing (ODR) support exists for ATM point-to-point permanent virtual circuits (PVCs).
ODR uses Cisco Discovery Protocol to propagate IP address information in hub-and-spoke topologies. When ODR is enabled, spoke
routers automatically advertise their subnets by using Cisco Discovery Protocol.
Cisco Discovery Protocol is disabled by default on ATM PVC interfaces. To enable Cisco Discovery Protocol, use the cdp run
command in global configuration mode and the cdp enable command in interface configuration mode on both ends of the PVC. To
enable ODR, use the router odr command in global configuration mode on the hub router, and turn off all dynamic-routing protocols
on the spoke routers. For details about configuring ODR, see the "Configuring On-Demand Routing" section in the IP Routing: ODR
Configuration Guide.
Cisco Discovery Protocol Support in IPv6
Cisco Discovery Protocol in IPv6 functions in the same way as in IPv4 and offers the same benefits. The IPv6 enhancement allows
Cisco Discovery Protocol to exchange IPv6 and neighbor addressing information. The enhancement also provides IPv6 information
to network management products and troubleshooting tools.
Benefits of Cisco Discovery Protocol
Cisco Discovery Protocol provides the following benefits:
• Allows systems using different network layer protocols to learn about one another.
• Facilitates management of Cisco devices by discovering them and discovering how they are configured.
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