Ecom Instruments ECOM-EF24F2G - Manual (Page 11)

1 Product Overview
3
ECOM ES24F2G the Gigabit Ethernet Switch User’s Manual V1.0
Port-based VLAN
ECOM-ES24F2G Fast Ethernet Switch fulfills the initial VLAN implementation as defining
VLAN membership by groups of switch ports. Port grouping is the most common method of
defining VLAN membership, and its configuration is straightforward. But, when a user moves from
one port to another, it takes a network manager to manually reconfigure VLAN membership.
With manual VLAN configuration, both the initial setup and all subsequent moves and changes are
controlled by the network administrator, enabling a high degree of control. Also moving users
manually with VLANs may actually be easier than moving users across router subnets.
Table Maintenance via Signaling
When an end-station broadcasts its first frame, the switch resolves the end-station’s attached port
with its VLAN membership in cached address tables. As VLAN membership changes, these address
tables can be manually updated by a system administrator at a management console.
802.1q VLAN Standard
In March, 1996, the IEEE 802.1 Internet-working Subcommittee completed the initial phase of
investigation for developing a VLAN standard. The standard, known as 802.1Q, represents a major
milestone in enabling VLANs to be implemented. Since the rapid deployment of LAN switching
from around 1995, the shift toward LAN switching as a replacement for local/departmental routers,
or even shared media devices (hubs) is just accelerating for now.
What is Priority Queuing?
Priority Queuing is a method of ensuring that high priority traffic gets delivered efficiently, even
when during bursts of high traffic load. In this way, traffic such as voice data and video (services
which are streaming) are prioritized, helping steady picture and sound quality.
ECOM-ES24F2G allows 2-level (High/Normal) Priority setting by any of the three types of
priority frames operations: TCP/IP TOS, VLAN tag or per Port priority frame operation.
The QoS setting for priority per port means that all packets received by the port will be priority
frames; ECOM-ES24F2G can also judge the priority of frames by checking the specific bits of
VLAN tag or TCP/IP TOS/DS included in the frame format. ECOM-ES24F2G will judge the
priority of frames by checking the specific bits recorded in the type field of packet format to ensure
the VLAN or TCP/IP TOS/DS status of packets, then set the threshold of VLAN or TCP/IP TOS/DS
to declare the priority of packet.
If you have any plans to implement network telephony or any sort of video conferencing, streaming
video/audio or any real-time applications on your network you will need ECOM-ES24F2G for
priority queuing. Its benefit is to dramatically improve the quality of priority services on the network.
If priority queuing is not implemented then the quality of these services will depend entirely on the
loads on your network. If network traffic is high, the service will not work properly.