No relevant resource is found in the selected language.

This site uses cookies. By continuing to browse the site you are agreeing to our use of cookies. Read our privacy policy>Search

Reminder

To have a better experience, please upgrade your IE browser.

upgrade

NE20E-S2 V800R010C10SPC500 Feature Description - Network Reliability 01

This is NE20E-S2 V800R010C10SPC500 Feature Description - Network Reliability
Rate and give feedback:
Huawei uses machine translation combined with human proofreading to translate this document to different languages in order to help you better understand the content of this document. Note: Even the most advanced machine translation cannot match the quality of professional translators. Huawei shall not bear any responsibility for translation accuracy and it is recommended that you refer to the English document (a link for which has been provided).
IPRAN Gateway Protection Solution

IPRAN Gateway Protection Solution

Service Overview

NodeBs and radio network controllers (RNCs) on an IP radio access network (IPRAN) do not have dynamic routing capabilities. Static routes must be configured to allow NodeBs to communicate with access aggregation gateways (AGGs) and allow RNCs to communicate with radio service gateways (RSGs) at the aggregation level. To ensure that various value-added services, such as voice, video, and cloud computing, are not interrupted on mobile bearer networks, a VRRP backup group can be deployed to implement gateway redundancy. When the master device in a VRRP backup group goes Down, a backup device takes over, ensuring normal service transmission and enhancing device reliability at the aggregation layer.

Networking Description

Figure 5-29 shows the network for the IPRAN gateway protection solution. A NodeB is connected to AGGs over an access ring or is dual-homed to two AGGs. The cell site gateways (CSGs) and AGGs are connected using the pseudo wire emulation edge-to-edge (PWE3) technology, which ensures connection reliability. Two VRRP backup groups can be configured on the AGGs and RSGs to implement gateway backup for the NodeB and RNC, respectively.

Figure 5-29 IPRAN gateway protection solution

Feature Deployment

Table 5-5 describes VRRP-based gateway protection applications on an IPRAN.

Table 5-5 VRRP-based gateway protection on an IPRAN

Network Layer

Feature Deployment

Usage Scenario

Deploy VRRP backup groups on AGGs to implement gateway backup for the NodeB.

Associate an mVRRP backup group with a service VRRP backup group.

To meet various service demands, different VRRP backup groups can be configured on AGGs to provide gateway functions for different user groups. Each VRRP backup group maintains its own state machine, leading to transmission of multiple VRRP packets on the AGGs. These packets use a significant amount of bandwidth when traversing the access network.

To simplify VRRP operations and reduce bandwidth consumption, an mVRRP backup group can be associated with service VRRP backup groups on AGGs. During this process, service VRRP backup groups function as gateways for the NodeB and are associated with the mVRRP backup group. The mVRRP backup group processes VRRP Advertisement packets and determines the master/backup status of the associated service VRRP backup group.

Associate an mVRRP backup group with a BFD session.

By default, when a VRRP backup group detects that the master device goes Down, the backup device attempts to preempt the Master state after 3 seconds (three times the interval at which VRRP Advertisement packets are broadcast). During this period, no master device forwards user traffic, which leads to traffic forwarding interruptions.

BFD can detect link faults in milliseconds. After an mVRRP backup group is associated with a BFD session and BFD detects a fault, a master/backup VRRP switchover is implemented, preventing user traffic loss. When the master device goes Down, the BFD module instructs the backup device in the mVRRP backup group to preempt the Master state and take over traffic. The status of the service VRRP backup group associated with the mVRRP backup group changes accordingly. This implementation reduces service interruptions.

Associate direct network segment routes with a service VRRP backup group.

During the traffic transmission between the NodeB and RNC, user-to-network and network-to-user traffic may travel through different paths, causing network operation, maintenance, and management difficulties. For example, the NodeB sends traffic destined for the RNC through the master AGG. The RNC sends traffic destined for the NodeB through the backup AGG. This implementation increases traffic monitoring costs. Association between direct network segment routes and a service VRRP backup group can be deployed to ensure that user-to-network and network-to-user traffic travels through the same path.

Deploy VRRP backup groups on RSGs to implement gateway backup for the RNC.

Deploy basic VRRP functions.

RSGs provide gateway functions for the RNC. Basic VRRP functions can be configured on the RSGs to implement gateway backup. In normal circumstances, the master device forwards user traffic. When the master device goes Down, the backup device takes over.

Associate a VRRP backup group with a BFD session.

A VRRP backup group can be associated with a BFD session to implement a rapid master/backup VRRP switchover when BFD detects a fault. When the master device goes Down, the BFD module instructs the backup device in the VRRP backup group to preempt the Master state and take over traffic. This implementation reduces service interruptions.

Associate direct network segment routes with a VRRP backup group.

Direct network segment routes can be associated with a VRRP backup group to ensure the same path for both user-to-network and network-to-user traffic between the NodeB and RNC.

Protection Switching Process

AGG1 and RSG1 are deployed as master devices. The following describes user traffic path changes when AGG1 goes Down and after AGG1 recovers.

As shown in Figure 5-30, in normal circumstances, the NodeB sends traffic through the CSGs to AGG1 over the primary pseudo wire (PW). AGG1 forwards the traffic to RSG1 through the P device. Then, RSG1 forwards the traffic to the RNC. The path for user-to-network traffic is CSG -> AGG1 -> P -> RSG1 -> RNC, and the path for network-to-user traffic is RNC -> RSG1 -> P -> AGG1 -> CSG.

When AGG1 goes Down, a primary/secondary PW switchover is performed. Traffic sent from the NodeB goes through the CSGs to AGG2 through the new primary PW. AGG2 forwards the traffic to RSG1 through the P device and RSG2. Then, RSG1 sends the traffic to the RNC. The path for user-to-network traffic is CSG -> AGG2 -> P -> RSG2 -> RSG1 -> RNC, and the path for network-to-user traffic is RNC -> RSG1 -> RSG2 -> P -> AGG2 -> CSG.

Figure 5-30 Traffic path after AGG1 goes Down

As shown in Figure 5-31, when AGG1 recovers, a primary/secondary PW switchover is performed, but a master/backup switchover is not performed in the mVRRP backup group. Therefore, traffic sent from the NodeB goes through the CSGs and AGG1 to AGG2 over the previous primary PW. AGG2 forwards the traffic to RSG1 through the P device and RSG2. RSG1 then forwards the traffic to the RNC. The path for user-to-network traffic is CSG -> AGG1 -> AGG2 -> P -> RSG2 -> RSG1 -> RNC, and the path for network-to-user traffic is RNC -> RSG1 -> RSG2 -> P -> AGG2 -> AGG1 -> CSG.

Figure 5-31 Traffic path after AGG1 recovers

When AGG1 recovers, it becomes the master device after a specified preemption delay elapses. AGG2 then becomes the backup device. Traffic sent from the NodeB goes through the CSGs to AGG1 over the previous primary PW. AGG1 sends the traffic to RSG1 through the P device. RSG1 then sends the traffic to the RNC. The path for user-to-network traffic is CSG -> AGG1 -> P -> RSG1 -> RNC, and the path for network-to-user traffic is RNC -> RSG1 -> P -> AGG1 -> CSG.

Translation
Download
Updated: 2019-01-02

Document ID: EDOC1100055473

Views: 12095

Downloads: 4

Average rating:
This Document Applies to these Products
Related Version
Related Documents
Share
Previous Next