ZTE 3G Bearer Network Solution

Two routers are setup as the IP bearer equipment of signaling and network services. MGW is connected to the routers via GE/POS link, and then the routers are connected to the service router of backbone network.

Default gateway protection is performed by the service gateway equipment using VRRP protocol; “rectangular” route protection is performed between the backbone routers and the service routers. To enhance link (route/forwarding tree) switch-over speed, BDF protocol between MGW and ROUTER can be considered activating. In this way, switch-over speed can be less than 1s.

In the 3G PS domain, SGSN and GGSN are interconnected through IP network. To ensure the transmission reliability of media streams, SGSN and GGSN are connected with ROUTER in dual-homing mode, using VRRP and BFD to accelerate network route re-convergence. Network security also needs to be considered as GGSN is connected with the Internet or traditional IP networks, therefore, the firewall equipment should be set between GGSN and external IP network. In this way, the speed of re-convergence can be less than 1s.

The 3G bearer network can be categorized into domestic networks and IP core networks. The domestic network usually is a dedicated network and consists of layer-2 and layer-3 switches and/or low-end routers as major equipment, which are used to bear signaling and media stream of the 3G local network. Due to small network size and low traffic, it is suggested to use IGP/SPT/RSPT as the major bearer protocol. The reliability and fast convergence of the local network would depend on Fast IGP and RSPT to provide second-level guarantee.

The IP core network is used to connect each 3G local network. It is suggested to use MPLS VPN, identify different services and signaling, and depend on MPLS FRR to provide 50ms reliability protection. Full interconnection between core nodes or connection between at least 2 links and other nodes can ensure high reliability of the network.

MAN can be located as IP Core of 3G bearer network, and 3G local network is regarded as access network.