D-Link DGS-3200-10 Product Manual - Page 75

xStack® DGS-3200 Series Layer 2 Gigabit Ethernet Managed Switch Egress Filter Settings Users can configure an egress filter on specific ports for unknown unicast and unregistered multicast packets. The Switch dro ps all unk nown un icast/multicast packets on egress ports when it dete cts un known unicast/multicast packets for egress ports. Therefore, a user can select which port is permitted or not permitted to receive unknown unicast/multicast packets. To view the following window, click L2 Features > Egress Filter Settings: Figure 3 - 2. Egress Filter Settings window The following fields can then be set: Parameter Description Unicast Select ports to filter unknown unicast packets. These packets will not be forwarded to those ports. Unselected ports will not filter unknown unicast packets and the packets may be forwarded to those ports. Multicast Select ports to filter unregistered multicast packets. These packets will not be forwarded to those ports. Unselected ports will not filter unregistered multicast packets and the packets may be forwarded to those ports. Click Apply to implement changes made. 802.1Q VLAN Understanding IEEE 802.1p Priority Priority tagging is a function defined by the IEEE 802.1p standard designed to provide a means of managing traffic on a network where many differen t typ es of d ata may b e tran smitted si multaneously. It is in tended to allev iate problems asso ciated with th e delivery of time critical d ata over congested networks. The quality of applicatio ns that are dependent on such time critical d ata, such as video conferencing, can be severely and adversely affected by even very small delays in transmission. Network dev ices th at are in compliance with th e IEEE 80 2.1p sta ndard h ave t he ab ility to recogn ize th e p riority lev el of d ata packets. These de vices can a lso as sign a priority lab el or tag to packets. C ompliant devices ca n al so st rip priority t ags f rom packets. This priority tag determines the packet's degree of expeditiousness and determines the queue to which it will be assigned. Priority t ags are gi ven values fr om 0 t o 7 wi th 0 being a ssigned t o t he l owest p riority dat a an d 7 as signed t o t he highest. T he highest priority tag 7 is generally only used for data associated with video or audio applications, which are sensitive to even slight delays, or for data from specified end users whose data transmissions warrant special consideration. The Switch allows you to fu rther tailor how p riority tagged data packets are han dled on your network. Using queues to manage priority tagged data allows you to specify its relative priority to suit the needs of your network. There may be circumstances where it wo uld be ad vantageous t o group t wo or more di fferently t agged packets i nto t he sa me que ue. Ge nerally, however, i t i s recommended that the highest priority queue, Queue 7, 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. Strict mode and weighted round robin system are 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 7, will clear 4 packets for every 1 packet cleared from Queue 0. Remember, the p riority queue settings on the Switch are for all po rts, and all devices connected to the Switch will be affected. This priority qu euing system will b e esp ecially b eneficial if you r network em ploys switch es with t he cap ability o f assign ing priority tags. 62