上海博达 EPON产品线和应用介绍.ppt

由于协议的限制，VLAN资源只有4K，这样如果要实现PUPV的VLAN规划，设备支持的用户数只有4千多，这显然是不够的。为了突破VLAN资源的限制，通常采用灵活QinQ技术，在用户侧标识内层VLAN，在汇聚OLT（BDCOM 8500）标识外层VLAN，这样就实现了对用户和业务的精细化标识 用户家庭放置一台小集线器，连接IPTV机顶盒、宽带上网PC。只需一根网线连接到家庭放置的小集线器上，楼道交换机或EoC根据端口封装不同的Vlan ID，此时同一个用户的家庭IPTV、上网PC分配了相同的内层Vlan ID。 楼道交换机通过EPON设备，汇聚到机房OLT S8500。OLT S8500根据Ethernet Type不同，封装不同的外层Vlan ID。举例来说，可以将IPTV的数据流，封装1000的外层Vlan ID,而给宽带上网的报文封装上1001的外层Vlan ID。 OLT再根据外层Vlan ID不同，将IPTV的数据流发送给BD R7600路由器，将宽带上网的数据流发送给BRAS设备。BD R7600路由器、BRAS设备对QinQ报文做终结，然后将数据转发到骨干网。同时保证回程数据流能够按原路返回。 因此，通过灵活QinQ功能，即可实现用户的精细化标识。 * 智能配用电试点项目（3） 智能配用电试点项目（4） Thank You! * Cross-bar When a packet is received on a line card in the cross-bar architecture router, the first check determines if the destination is reachable via an output interface on the same line card. If so, the packet is copied to the local packet memory and switched by the line card itself. If the destination is reachable on another line card, the packet is transferred via the cross-bar fabric to the destination line card, which in turn transmits it on its medium. The cross-bar interconnection can be treated as a private high-bandwidth point-to-point connection between line card pairs. 分布式 When a packet is received on a line card in the distributed architecture, the first check determines if the destination is reachable via an output interface on the same line card. If so, the packet is copied to the local packet memory and switched by the line card itself. If the destination is reachable on another line card, the packet is copied to the fast shared memory (usually implemented with SRAM). The central CPU switches the packet to the destination line card, which in turn transmits it on its medium. This procedure involves the shared bus and presents a performance penalty, as multiple shared resources are used. Therefore it is imperative to implement distributed architectures by analyzing traffic flows in the network, and try to configure the chassis for its maximum performance. 集中式 Wh