An important technical parameters 1, VLAN support more The backbone switches, using Ethernet technology can easily achieve VLAN, VLAN, the number of its support than the ordinary Ethernet Switches To many, in general, can support 4k a VLAN. In some backbone switch, or even can be done to support the port VLAN, VLAN number that is no longer limited to a maximum of 4k a 802.1q VLAN protocol limitations, can do to support n × 4k (n that port number) a VLAN. In some backbone switch, it can be done to support the double (multiple) VLANTAG, this could make VLAN-based forwarding has a hierarchy, but also break the 4k limit on the number one VLAN .|
2, more MAC address table Ethernet forwarding is based mainly on the MAC address table. In the backbone switch, the access port density is relatively high, but can also hang over the next ordinary LANSwitch, are also more user access, such as the entire enterprise network to all users or a small community of users. Therefore, the number of its MAC address table often 10k or more, usually in the 32k ~ 256k. Therefore, when choosing the backbone switch, MAC address forwarding number is an important indicator.
3, support the three-tier exchange As a backbone switch, it must have three exchange capacity, which is the backbone of one of the salient features of the switch. Basically normal LANSwitch switch can support MAC address forwarding the second floor, and some have three-tier forwarding capability, allowing a limited three-routing capabilities. But speaking as a backbone switch, supporting a cross-VLAN forwarding ability is a must have. This is the backbone switch in the enterprise network or campus network, MAN exchange interface separated from the network location. Therefore, the three switches must have three interfaces. In general, three interface is divided into three logical interface VLAN as the basic unit. In each VLAN, the requirement has its own separate subnet address. Therefore, the backbone switch, VLAN support subnet gateway address is a number of more important indicators.
4, to support more protocols "One route, several exchange" is the exchange of routing switches, the guiding ideology. But this three-forward thinking for forwarding the first packet of time-consuming, especially in the backbone layer switches, which restrict the forwarding rate forwarding mechanisms. Now, the key switches have basically achieved the maximum matching in hardware forwarding mechanism, so it can handle three-wire-speed forwarding. Meanwhile, the number of three-forwarding support is an important indicator of the backbone switch. In general, backbone switches and backbone Router Supported by a considerable number of routing table. Key switch on the routing protocol support is also very rich and can support RIP protocol, OSPF protocol, IS-IS protocol, BGP protocol. The support of these routing protocols can not fully guarantee the backbone switch can run in the enterprise network, or even run in tandem carrier layer, the backbone layer.
5, flow classification and QoS Support for traffic classification and QoS guarantee is one of the important backbone switch feature. Backbone switch relatively large number of users access, the user requests the network is complicated and unorganized. Therefore, the backbone switch, it should be able to cater for different users, different network environment, QoS-based traffic classification and filtering. The number of flow classification number, will largely affect the backbone switch in the PoP's operational capacity and meet growing business user needs and security assurances. So now the backbone switches
should support QoS-based traffic classification and bandwidth guarantees.
6, higher security requirements
I am China Home Appliances writer, reports some information about soft cat carriers , modular dog kennels.
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