NetEngine 8000 M6, M1D, and M1C V800R023C10SPC500 Configuration Guide
Configuring an Interface to Support PPP
Configure an interface to support PPP so that it can implement point-to-point (P2P) traffic transmission.
Usage Scenario
PPP is a link layer protocol that transmits network layer packets over P2P links.
To monitor link status in real time, configure link status monitoring parameters so that link faults can be identified in time. A PPP link does not require that the peer route and local route be on the same network segment. To avoid incorrect routing information, prohibit the addition of the peer host route to the local routing table of direct routes.
Pre-configuration Tasks
Before configuring an interface to support PPP, connect the interface and set physical parameters to ensure that the physical status of the interface is Up.
- Configuring PPP as the Link Layer Protocol of an Interface
- (Optional) Configuring PPP Negotiation Parameters
- (Optional) Configuring PPP Link Status Monitoring
- (Optional) Prohibiting a Local Device from Adding the Peer Host Route to the Local Routing Table of Direct Routes
- Verifying the PPP Configuration
Configuring PPP as the Link Layer Protocol of an Interface
Configure PPP as the link layer protocol of an interface for the interface to implement P2P traffic transmission.
(Optional) Configuring PPP Negotiation Parameters
For a PPP link to be established between two communicating devices that have PPP enabled, configure the following PPP negotiation parameters: MRU, negotiation timeout period.
Context
A PPP link is established between two communicating devices after successful LCP negotiation and NCP negotiation. After the physical link goes Up, the two devices enter the link establishment phase, during which one device initiates LCP negotiation.
Negotiation Parameter |
Usage Scenario |
Negotiation Phase |
|---|---|---|
PPP MRU |
If an MTU is configured on an interface of a PPP link, enable the PPP MRU negotiation function so that interfaces on both ends of the PPP link have the same MTU, which ensures proper data transmission. If the interfaces have different MTUs, the smaller MTU will be selected as the PPP link MTU after the negotiation. |
LCP negotiation phase |
Negotiation timeout period |
During LCP negotiation, the local device sends an LCP negotiation packet to the remote device. If the local device does not receive a reply packet from the remote device within the specified negotiation timeout period, the local device resends an LCP negotiation packet. |
LCP negotiation phase |
In VS mode, the configuration of Negotiation timeout period is supported only on the admin VS.
(Optional) Configuring PPP Link Status Monitoring
The PPP link status can be effectively monitored using the PPP link status monitoring function.
Context
The parameters for PPP link status monitoring are as follows:
Keepalive time
Polling interval
The polling interval determines how often an interface sends a Keepalive message. When PPP is specified as the link layer protocol on the interface, the interface sends a Keepalive message to its peer device at the set polling interval. If the interface fails to receive a Keepalive message from the peer after five polling intervals, the interface considers the peer device to be faulty and sets the PPP link to Down. In situations with unfavorable network delay or significant congestion, you can increase the polling interval to reduce network flapping.
In situations with unfavorable network delay or significant congestion, a short Keepalive time may cause network flapping. Conversely, a long Keepalive time would lead to slow link detection. Therefore, make sure that the Keepalive time is appropriate and fits the network situations.
(Optional) Prohibiting a Local Device from Adding the Peer Host Route to the Local Routing Table of Direct Routes
To avoid incorrect routing information in the local routing table, you can prohibit a local device from adding the peer host route to the local routing table of direct routes.
Context
Devices on both ends of a PPP link may have IP addresses at different network segments. When the two devices communicate with each other, one device automatically adds the host route of the other end to the local routing table of direct routes. If one end has an incorrect IP address configured, incorrect routing information will be advertised on the network. To prevent incorrect routing information, prohibit the local device from adding the peer host route to the local routing table of direct routes.
Procedure
- Run system-view
The system view is displayed.
- Run interface interface-type interface-number
The interface view is displayed.
- Run ppp peer hostroute-suppress
The device is prohibited from adding the peer host route to the local routing table of direct routes.
- Run commit
The configuration is committed.
Verifying the PPP Configuration
After configuring PPP as the link layer protocol, verify the configuration.
Procedure
- Run the display interface [ interface-type [ interface-number ] ] command to check the status of and statistics about a specific PPP-enabled interface.
- Run the display ppp information interface interface-type interface-number command to check PPP link information about a specific interface.
- Configuring PPP as the Link Layer Protocol of an Interface
- (Optional) Configuring PPP Negotiation Parameters
- (Optional) Configuring PPP Link Status Monitoring
- (Optional) Prohibiting a Local Device from Adding the Peer Host Route to the Local Routing Table of Direct Routes
- Verifying the PPP Configuration