In my last post, I discussed multicasts and some of the basic concepts. This time, I'm going to discuss technologies used by switches and routers to enable and configure multicasts. Specifically, I'm going to dive into addressing and IGMP. Understanding the details behind multicasts helps understand configuring multicasts as well as the issues limiting the use of multicasts on the web.
It's occurred to me that readers monitoring our RSS feeds can't tell when we add new products to the charts. So, starting now, I'll be announcing additions via short news items.
Peplink's Balance 30 has been added to the Router Charts. It's a three-WAN router with about 20 Mbps routing throughput and built-in four port 10/100 switch.
With the growth of IPTV and other IP media streaming technologies, applications for multicast technology are increasing. Live Video broadcasts and VoIP applications are viable uses for real time transmissions over an IP network from a single source to multiple recipients.
Most data transmissions are unicasts, which are a one-to-one data stream sent from one device to another device. Email, web surfing, and file downloads are all examples of unicasts, even for the busiest sites or most downloaded files. Although a single web page may be visited thousands of times each day, each time it is viewed it is individually transmitted to the requestor's PC as a unicast.
D-Link today announced the expansion of its "Green Ethernet" switch line with the addition of 16 and 24 port unmanaged gigabit models.
New hardware revisions of the DGS-1016D 16-port and DGS-1024 24-port unmanaged gigabit switches now support the same power-saving features introduced on the DGS-2205 and DGS-2208 5 and 8 port switches last October.
In my last two posts on this subject, I've covered some of the basics and tools used to perform packet captures, highlighting the well known software from Wireshark. In this installment, I'm going to show how I used Wireshark packet captures to solve a real network problem.
Using packet papture software like Wireshark is a useful troubleshooting technique that can be used to examine packets and gather details to help find the root of a problem. In my previous post, I talked a little bit about how to use Wireshark and walked through some steps to run a simple packet capture from a PC. This time, I'm going to go a bit deeper into the how to for doing packet captures.
One of the features I've seen in newer small network routers is the inclusion of a packet sniffer/capture/trace tool within the diagnostic menus of the device. Routers I've recently tested with this functionality include the SonicWall TZ190W, D-Link DFLCPG310, and Netgear's newly released FVX538 and FVS336G.
In each case, these devices have the ability to capture packets on a specific WAN port and/or on the LAN interface. Some of these routers have more sophisticated filtering capabilities than the other, but they all seem to have the same basic functionality of capturing packets.
Apposite Technologies has announced the release of the Linktropy Mini, a portable, low cost version of its Linktropy WAN emulator.
The Linktropy Mini emulates link bandwidth, delay, jitter, packet loss, and other basic network impairments on up to 100 Mbps bi-directional network links. The Mini measures only 11" W x 7" D x 1.75" H and weighs 3.5 lbs. making it easy to transport and use.
The Linktropy Mini is available immediately for $1975 MSRP.
Digitimes today reported that Zyxel Communications has filed a complaint against D-Link and Waveplus Technology for switch-related patent infringements. Chip supplier Waveplus is being blamed as the cause of the dispute.
The dispute is over a < $20 D-Link switch that is sold only in Russia and that Zyxel claims is "very similar" to a Zyxel design.
Zyxel said it has not yet decided the amount of monetary damages it will claim and D-Link said that it is "completely protected from any patent controversy" and that no operations should be affected by the dispute.
MoCA chipset manufacturer Entropic today announced that D-Link will have a retail product by the end of Q1.
The D-Link DXN-220 MoCA MediaBridge is an Ethernet to coax MoCA-compliant bridge using Entropic's EN2210 chipset. The announcement didn't quote any bandwidth numbers, but MoCA 1.1 has a PHY (raw) data rate of 270 Mbps. So expect a maximum application (useful) data rate of around half that.
No pricing was announced.
Read the review.
HotBrick Network Solutions recently introduced the VPN 800/2G, a dual WAN router with IPsec endpoint capability.
The router supports 9 load balancing methods and automatic failover on its dual 10/100/1000 Ethernet WAN ports. A built-in 8 port 10/100 plus two 10/100/1000 switch provides LAN client connection.
100 simultaneous IPSec VPN tunnels with DES, 3DES and AES encryption support remote client or gateway-to-gateway connection. HotBrick's standard VPN client has no node license limitation.
Other features include a SPI+NAT firewall, one-to-one NAT and port-based QoS for bandwidth management.
The VPN 800/2G is available immediately at an MSRP of $899.
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