Loop guard (LG) allows you to configure the Switch to shut down a port if it detects that packets sent out on that port loop back to the Switch. While you can use Spanning Tree Protocol (STP) to prevent loops in the core of your network. STP cannot prevent loops that occur on the edge of your network.

Loop guard is designed to handle loop problems on the edge of your network. This can occur when a port is connected to a Switch that is in a loop state. Loop state occurs as a result of human error. It happens when two ports on a switch are connected with the same cable. When a switch in loop state sends out broadcast messages the messages loop back to the switch and are re-broadcast again and again causing a broadcast storm.

If a switch (not in loop state) connects to a switch in loop state, then it will be affected by the switch in loop state in the following way:

The following table describes the labels in this screen.

Port mirroring allows you to copy a traffic flow to a monitor port (the port you copy the traffic to) in order that you can examine the traffic from the monitor port without interference.

Use this screen to select a monitor port and specify the traffic flow to be copied to the monitor port.

The following table describes the labels in this screen.

Traditionally, IP packets are transmitted in one of either two ways – Unicast (one sender to one recipient) or Broadcast (one sender to everybody on the network). Multicast delivers IP packets to just a group of hosts on the network.

IGMP (Internet Group Management Protocol) is a network-layer protocol used to establish membership in a multicast group – it is not used to carry user data. Refer to RFC 1112, RFC 2236 and RFC 3376 for information on IGMP versions 1, 2 and 3 respectively.

In IPv4, a multicast address allows a device to send packets to a specific group of hosts (multicast group) in a different subnetwork. A multicast IP address represents a traffic receiving group, not individual receiving devices. IP addresses in the Class D range (224.0.0.0 to 239.255.255.255) are used for IP multicasting. Certain IP multicast numbers are reserved by IANA for special purposes (see the IANA website for more information).

A Switch can passively snoop on IGMP packets transferred between IP multicast routers or switches and IP multicast hosts to learn the IP multicast group membership. It checks IGMP packets passing through it, picks out the group registration information, and configures multicasting accordingly. IGMP snooping allows the Switch to learn multicast groups without you having to manually configure them.

The Switch forwards multicast traffic destined for multicast groups (that it has learned from IGMP snooping or that you have manually configured) to ports that are members of that group. IGMP snooping generates no additional network traffic, allowing you to significantly reduce multicast traffic passing through your Switch.

The Switch can perform IGMP snooping on up to 16 VLANs. You can configure the Switch to automatically learn multicast group membership of any VLANs. The Switch then performs IGMP snooping on the first 16 VLANs that send IGMP packets. This is referred to as auto mode. Alternatively, you can specify the VLANs that IGMP snooping should be performed on. This is referred to as fixed mode. In fixed mode the Switch does not learn multicast group membership of any VLANs other than those explicitly added as an IGMP snooping VLAN.

This screen shows the IPv4 multicast group information.

The following table describes the labels in this screen.

The following table describes the labels in this screen.

The following table describes the labels in this screen.

This screen allows you to add an IGMP snooping VLAN or edit an existing one.

To access this screen, click the Add/Edit button or select an entry from the list and click the Add/Edit button.

The following table describes the labels in this screen.

A multicast MAC address or multicast IP address is the MAC address or IP address of a multicast group, and not a receiving device.

A static multicast address is a multicast MAC address or multicast IPv4 address that has been manually entered in the multicast table. This identifies the destination of the multicast content. Multicast IPv4 addresses uses the Class D IP addresses range 224.0.0.0 to 239.255.255.255. Multicast MAC addresses have a “1” as the last binary bit of the first octet pair (for example, 01:00:5e:00:00:0A). Static multicast addresses do not age out.

If a multicast group has no members, then the Switch cannot forward to specific ports unless you configure static (manual) multicast entries. The Switch will either flood the multicast frames to all ports (default) or drop them. With static multicast forwarding, you can forward these multicasts to ports within a VLAN group.

Use this screen to view and configure static multicast MAC addresses for ports to receive the multicast stream.The following table describes the labels in this screen.

Use this screen to add a static multicast MAC address rule for ports to receive the multicast stream.

Click Add/Edit, or select an entry and click Add/Edit in the SWITCHING > Multicast > Static Multicast Forwarding By MAC to display this screen.

The following table describes the labels in this screen

IP-based security products use a specific protocol for communication. One of the most common protocols is ONVIF (Open Network Video Interface Forum). ONVIF is a standard interface for interoperability of IP-based security products.

When ONVIF is enabled and configured, the Switch can obtain information from connected ONVIF-compatible devices, such as a device’s system name and IP address. This lets you know which ONVIF-compatible devices, for example IP cameras and NVR (network video recorders), are connected to the Switch.

This screen lets you turn on the ONVIF protocol on the Switch and its Ethernet ports.

The following table describes the labels in this screen.

The following table describes the labels in this screen.

Quality of Service (QoS) is used to prioritize source-to-destination traffic flows. All packets in the flow are given the same priority. You can use CoS (class of service) to give different priorities to different packet types.

DiffServ is a class of service (CoS) model that marks packets so that they receive specific per-hop treatment at DiffServ-compliant network devices along the route based on the application types and traffic flow. Packets are marked with DiffServ Code Points (DSCPs) indicating the level of service desired. This allows the intermediary DiffServ-compliant network devices to handle the packets differently depending on the code points without the need to negotiate paths or remember state information for every flow. In addition, applications do not have to request a particular service or give advanced notice of where the traffic is going.

Activate DiffServ to apply marking rules or IEEE 802.1p priority mapping on the selected ports.

The following table describes the labels in this screen.

You can configure the DSCP to IEEE 802.1p mapping to allow the Switch to prioritize all traffic based on the incoming DSCP value according to the DiffServ to IEEE 802.1p mapping table.

The following table shows the default DSCP-to-IEEE802.1p mapping.

The following table describes the labels in this screen.

Queuing is used to help solve performance degradation when there is network congestion. Use the Queuing Method screen to configure queuing algorithms for outgoing traffic. See also Priority Queue Assignment in the SWITCHING > QoS > Priority Queue screen and 802.1p Priority in the PORT > Port Setup > Port Setup screen for related information.

Queuing algorithms allow switches to maintain separate queues for packets from each individual source or flow and prevent a source from monopolizing the bandwidth.

Strictly Priority Queuing (SPQ) services queues based on priority only. As traffic comes into the Switch, traffic on the highest priority queue, Q7 is transmitted first. When that queue empties, traffic on the next highest-priority queue, Q6 is transmitted until Q6 empties, and then traffic is transmitted on Q5 and so on. If higher priority queues never empty, then traffic on lower priority queues never gets sent. SPQ does not automatically adapt to changing network requirements.

Weighted Fair Queuing is used to guarantee each queue's minimum bandwidth based on its bandwidth weight (portion) (the number you configure in the Weight field) when there is traffic congestion. WFQ is activated only when a port has more traffic than it can handle. Queues with larger weights get more guaranteed bandwidth than queues with smaller weights. This queuing mechanism is highly efficient in that it divides any available bandwidth across the different traffic queues. By default, the weight for Q0 is 1, for Q1 is 2, for Q2 is 3, and so on.

Round Robin Scheduling services queues on a rotating basis and is activated only when a port has more traffic than it can handle. A queue is given an amount of bandwidth irrespective of the incoming traffic on that port. This queue then moves to the back of the list. The next queue is given an equal amount of bandwidth, and then moves to the end of the list; and so on, depending on the number of queues being used. This works in a looping fashion until a queue is empty.

Weighted Round Robin Scheduling (WRR) uses the same algorithm as round robin scheduling, but services queues based on their priority and queue weight (the number you configure in the queue Weight field) rather than a fixed amount of bandwidth. WRR is activated only when a port has more traffic than it can handle. Queues with larger weights get more service than queues with smaller weights. This queuing mechanism is highly efficient in that it divides any available bandwidth across the different traffic queues and returns to queues that have not yet emptied.

Use this screen to set priorities for the queues of the Switch. This distributes bandwidth across the different traffic queues.

The following table describes the labels in this screen.

IEEE 802.1p defines up to eight separate traffic types by inserting a tag into a MAC-layer frame that contains bits to define class of service. Frames without an explicit priority tag are given the default priority of the ingress port. Use this screen to configure the priority level-to-physical queue mapping. The Switch has eight physical queues that you can map to the eight priority levels.

On the Switch, traffic assigned to higher index queues gets through faster while traffic in lower index queues is dropped if the network is congested.

Use this screen to assign priority level to each queue.

The following table describes the related labels in this screen.

Bandwidth control means defining a maximum allowable bandwidth for incoming and/or out-going traffic flows on a port.

The following table describes the related labels in this screen.