The development status of Policy Routing Technology

The Policy Routing Technology in China has developed very rapidly. Here we mainly introduce the terms of the Policy Routing Technology, including the functional features of the Policy Routing Technology. The rapid development of the Internet provides users with more access methods. For example, colleges and universities can access the internet through the education network or telecom network. To allow different users to access internet resources in different ways.

Users have higher requirements on the routing function of layer-3 switches. H3C's Policy Routing Technology is a technology that identifies different network packets and forwards them according to preset policies. It can identify and classify network packets according to different key fields, to determine the forwarding policy. Policy Routing technology can effectively control the flow and behavior of network user data packets. Policy Routing is at the IP layer. before forwarding an IP address, if a message hits the rule corresponding to a policy routing technology, the corresponding policy routing technology action is required, actions include redirecting to the specified next hop, and marking the remark such as TOS, IP priority, or DSCP), and then querying the FIB table based on the destination IP address of the redirection next hop instead of the packet for IP forwarding.

1 Term

NEXTHOP

Redirect Next Hop: In the process of Policy Routing Technology, replace the destination ip address of the packet to find the route table to get the ip address of the next hop.

ACLAccessControlList)

Access Control List: contains a series of rules. These rules can be used to match a message to determine the corresponding policy routing action for the message.

FIB (ForwardingInformationBase)

Forwarding info table: FIB is the core data of layer-3 forwarding, which is used to forward IP packets.

PBR (PolicyBasedRouting)

Policy Routing: routes packets based on predefined policies.

TOS (TypeofService)

Service type: a flag in the IP packet header for traffic control.

NP (NetworkProcessor)

Network Processor: a programmable, high-performance dedicated network processor for data packet processing.

2. Features of Policy Routing

PBR uses keywords to classify data packets and uses different policy routing technologies to forward data packets. The keywords used are data packets themselves or related feature items:

◆ Source IP address
◆ Destination IP address
◆ Source port number
◆ Destination port number
◆ IP protocol type

PBR can classify data packets based on these keywords. Different Categories use different policy routes. Policy Routing is based on the key feature words of data packets. It can be combined based on the key feature words to make policy routing more flexible.

3. Inbound interface binding Policy Routing

An inbound interface refers to an interface on the Intranet. By binding a Policy Routing technical configuration on the VLAN interface on the Intranet side, all packets entering the VLAN interface on the Intranet can be classified according to certain rules, and route forwarding according to different policies. An Intranet interface generally corresponds to a subnet. Generally, the routing and forwarding policies for a subnet are the same. Therefore, this method can simplify the complexity of ACL rules. Generally, due to chip restrictions, the number of inbound interface configuration rules is limited.

4. Outbound interface binding Policy Routing

An outbound interface is an interface on the internet side. It is generally connected to a larger LAN or internet. By binding policy routing technology configuration on the VLAN interface on the public network, all packets sent from the interface in the Intranet can be classified according to certain rules and forwarded according to different policies. The outbound interface Policy Routing Technology configuration is usually not restricted by the chip. The number of rules can reach 3000.