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- Table of Contents
-
- 04-Layer 3 Configuration Guide
- 00-Preface
- 01-ARP Configuration
- 02-IP Addressing Configuration
- 03-DHCP Configuration
- 04-DHCPv6 Configuration
- 05-DNS Configuration
- 06-IPv6 DNS Configuration
- 07-NAT Configuration
- 08-Adjacency Table Configuration
- 09-Flow Classification Configuration
- 10-IPv6 Basics Configuration
- 11-IP Performance Optimization Configuration
- 12-IP Routing Basics
- 13-Static Routing Configuration
- 14-IPv6 Static Routing Configuration
- 15-GRE Configuration
- 16-RIP Configuration
- 17-RIPng Configuration
- 18-Policy-Based Routing Configuration
- Related Documents
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| Title | Size | Download |
|---|---|---|
| 08-Adjacency Table Configuration | 37.20 KB |
Configuring adjacency table
The adjacency table feature only applies to hardware forwarding, but not software forwarding.
The adjacency table feature does not apply to Ethernet networks that use ARP for storing and managing neighbor information.
Overview
An adjacency table stores information about active neighbors, including neighbor network layer address (next hop), outgoing interface, link layer service type, and link layer address. The PVC information is displayed for ATM as the link layer address for ATM, and no link layer address is available for PPP.
The concept of neighbor is relevant to network layer. Node B may be an IP neighbor, but not an IPX neighbor of node A. Also, a neighbor in the active state is in relation to network layer. The adjacency table feature only supports the neighbor concept in relation to IP.
A device can be connected with its neighbors through multiple link layer protocols, such as PPP, ATM, and frame relay (FR).
The products supporting hardware forwarding can apply the adjacency table to the drivers to implement hardware forwarding. In hardware forwarding, the link layer header of the packet to be forwarded is quickly filled according to the adjacency table, and then the packet is forwarded through the outgoing interface.
Adjacency table fields
Fields in the adjacency table are described as follows:
· Routing interface—Outgoing interface in a route entry.
· Physical interface—Such as serial interface, POS interface, and ATM interface.
· Logical interface—An abstract interface that does not correspond to any physical entity and is used for adjacency table implementation, for example, Virtual-Ethernet interface and Virtual-Template interface.
· Service type—Type of service corresponding to the adjacency table, such as PPP and IP over ATM.
· Action type—Action to take on the packet that matches the entry, forward or drop.
· Link media type—Related to the link layer protocol used by the outgoing interface. P2P indicates point-to-point, such as PPP.
· Link head information (IPv6)—Information about the link layer header corresponding to the IPv6 protocol.
Displaying and maintaining adjacency table
|
Task |
Command |
Remarks |
|
Display IPv4 adjacency table entries. |
display adjacent-table { all | physical-interface interface-type interface-number | routing-interface interface-type interface-number } [ count | verbose ] [ | { begin | exclude | include } regular-expression ] |
Available in any view. |
|
Display IPv6 adjacency table entries. |
display ipv6 adjacent-table { all | physical-interface interface-type interface-number | routing-interface interface-type interface-number } [ count | verbose ] [ | { begin | exclude | include } regular-expression ] |
Available in any view. |
