Planet WGSW-2840 Инструкция по эксплуатации онлайн [44/104] 65303

the same queue. Generally, however, it is recommended that the highest priority queue, Queue 1, be reserved for

data packets with a priority value of 7. Packets that have not been given any priority value are placed in Queue 0

and thus given the lowest priority for delivery.

A weighted round robin system is employed on the Switch to determine the rate at which the queues are emptied

of packets. The ratio used for clearing the queues is 4:1. This means that the highest priority queue, Queue 1, will

clear 4 packets for every 1 packet cleared from Queue 0.

Remember, the priority queue settings on the Switch are for all ports, and all devices connected to the Switch will

be affected. This priority queuing system will be especially beneficial if your network employs switches with the

capability of assigning priority tags.

VLAN Description

A Virtual Local Area Network (VLAN) is a network topology configured according to a logical scheme rather than

the physical layout. VLAN can be used to combine any collection of LAN segments into an autonomous user

group that appears as a single LAN. VLAN also logically segment the network into different broadcast domains so

that packets are forwarded only between ports within the VLAN. Typically, a VLAN corresponds to a particular

subnet, although not necessarily.

VLAN can enhance performance by conserving bandwidth, and improve security by limiting traffic to specific

domains.

A VLAN is a collection of end nodes grouped by logic instead of physical location. End nodes that frequently

communicate with each other are assigned to the same VLAN, regardless of where they are physically on the

network. Logically, a VLAN can be equated to a broadcast domain, because broadcast packets are forwarded to

only members of the VLAN on which the broadcast was initiated.

NOTICE:

1. No matter what basis is used to uniquely identify end nodes and assign these nodes VLAN

membership, packets cannot cross VLAN without a network device performing a routing function

between the VLAN.

2. The Switch supports Port-based VLAN and IEEE 802.1Q VLAN. The port untagging function can

be used to remove the 802.1 tag from packet headers to maintain compatibility with devices that

are tag-unaware.

3. The Switch's default is to assign all ports to a single 802.1Q VLAN named DEFAULT_VLAN. As

new VLAN is created, the member ports assigned to the new VLAN will be removed from the

DEFAULT_ VLAN port member list. The DEFAULT_VLAN has a VID = 1.

Port-based VLAN

Port-based VLAN limit traffic that flows into and out of switch ports. Thus, all devices connected to a port are

members of the VLAN(s) the port belongs to, whether there is a single computer directly connected to a switch, or