Cisco Cisco IOS Software Release 12.2(27)SBC
Cisco Express Forwarding—SNMP CEF-MIB Support
Information About Cisco Express Forwarding—SNMP CEF-MIB Support
3
Cisco IOS Release 12.2(31)SB2
•
•
Cisco Express Forwarding Functional Overview
CEF is an advanced Layer 3 IP switching technology. It uses a Forwarding Information Base (FIB) to
make IP destination prefix-based switching decisions. The FIB is conceptually similar to a routing table
or information base. It maintains the forwarding information contained in the IP routing table. When
routing or topology changes occur in the network, the IP routing table is updated, and those changes are
propagated to the FIB. The FIB maintains next-hop address information based on the information in the
IP routing table. The two main components of CEF operation are the FIB and Adjacency tables.
make IP destination prefix-based switching decisions. The FIB is conceptually similar to a routing table
or information base. It maintains the forwarding information contained in the IP routing table. When
routing or topology changes occur in the network, the IP routing table is updated, and those changes are
propagated to the FIB. The FIB maintains next-hop address information based on the information in the
IP routing table. The two main components of CEF operation are the FIB and Adjacency tables.
CEF uses adjacency tables to prepend Layer 2 addressing information. The adjacency table maintains
Layer 2 next-hop addresses for all FIB entries. Nodes in the network are said to be adjacent if they can
reach each other with a single hop across a link layer. CEF discovers and solves adjacencies and
populates the adjacency tables.
Layer 2 next-hop addresses for all FIB entries. Nodes in the network are said to be adjacent if they can
reach each other with a single hop across a link layer. CEF discovers and solves adjacencies and
populates the adjacency tables.
CISCO-CEF-MIB Benefits
Command-line interface (CLI) show commands are available to obtain CEF operational information.
Managing CEF using the CLI can be a time consuming task. The increasing capacity of Cisco routers
makes parsing through the show commands output to obtain the needed CEF operational parameters
more and more difficult.
Managing CEF using the CLI can be a time consuming task. The increasing capacity of Cisco routers
makes parsing through the show commands output to obtain the needed CEF operational parameters
more and more difficult.
In Cisco IOS Release 12.2(31)SB and later releases, the CISCO-CEF-MIB allows you to manage and
monitor the CEF operation using SNMP. In addition, you can configure SNMP to notify you if CEF
encounters errors.
monitor the CEF operation using SNMP. In addition, you can configure SNMP to notify you if CEF
encounters errors.
With the CISCO-CEF-MIB introduced with the Cisco Express Forwarding—SNMP CEF-MIB Support
feature, you can access in real time operational information stored in the FIB and adjacency tables,
switching statistics, information on resource failures, and configure parameters related to CEF features
by utilizing a MIB implementation based on SNMP. This information is accessed using get and set
commands entered on the network management system (NMS) workstation or host system for which
SNMP has been implemented. The NMS workstation is also known as the SNMP manager.
feature, you can access in real time operational information stored in the FIB and adjacency tables,
switching statistics, information on resource failures, and configure parameters related to CEF features
by utilizing a MIB implementation based on SNMP. This information is accessed using get and set
commands entered on the network management system (NMS) workstation or host system for which
SNMP has been implemented. The NMS workstation is also known as the SNMP manager.
CEF is available in all Cisco routers. However, CISCO-CEF-MIB support of CEF management is
dependent on the new infrastructure introduced in Cisco IOS Release 12.2(22)S.
dependent on the new infrastructure introduced in Cisco IOS Release 12.2(22)S.
The implementation of the CISCO-CEF-MIB in Cisco IOS Release 12.2(31)SB2 manages CEF
instances running on the Route Processor (RP). Information about CEF running on the line cards is
available to the RP about CEF peers only.
instances running on the Route Processor (RP). Information about CEF running on the line cards is
available to the RP about CEF peers only.
The CISCO-CEF-MIB supports configuration and monitoring for both IP Versions, IP Version 4 (IPv4)
and Version 6 (IPv6).
and Version 6 (IPv6).
CEF Information Managed by the CISCO-CEF-MIB
SNMP has historically been used to collect network information. SNMP permits retrieval of critical
information from network elements such as routers, switches, and workstations.
information from network elements such as routers, switches, and workstations.