The TL-SG2216 offers multiple options for configuring Quality of Service (QoS). Traffic can be prioritized by port, by 802.1p values, and by DSCP values.
I think it is simpler to think of the TL-SG2216's QoS configurations in three steps.
- The TL-SG2216 allows you to map port priority and DSCP values to 802.1p CoS values.
- CoS values are mapped to four different queues on the TL-SG2216 labeled as TC0-TC3, with TC0 the lowest priority queue and TC3 the highest priority queue.
- Traffic queues are serviced based on one of four scheduling modes; Strict Priority, Weighted Round Robin, Strict Priority/Weighted Round Robin, and Equal (default).
The defaults on the TL-SG2216 make it easy. All ports have a default CoS set to 0, there is a standard mapping of DSCP to CoS values, and the CoS values are already mapped to the four different queues. All you have to do to enable QoS prioritization on the TL-SG2216 is click to enable DSCP and select a scheduling mode other than Equal. You can then customize the QoS settings if needed.
The TL-SG2216 also has the option to control traffic by applying ingress and egress bandwidth limits per port. In the screenshot below, I've applied ingress and egress bandwidth limits of 1024 Kbps to port 16.
TP-LINK TL-SG2216 Rate limiting
I validated the TL-SG2216's bandwidth limit functionality by running iperf throughput tests through port 16 before and after I applied bandwidth limits. My throughput before I applied the limits ranged from 271-324 Mbps and after I applied the limits was exactly 1.17 Mbps as you can see in the below. Recall that I set my limit at 1024 Kbps, which is approximately 1 Mbps.
TP-LINK TL-SG2216 Rate limit verification
Finally, the TL-SG2216 provides three storm control options that allow you to protect your network against devices flooding the network with excess traffic. This is useful, as I've seen network performance degrade due to a faulty network card on a PC flooding the network with meaningless data.
Per-port storm control options on the TL-SG2216 are to set a broadcast rate limit, a multicast rate limit, and a UL frame rate limit. (A UL frame is a frame with a destination MAC address that isn't in the MAC table. Default switch behavior on such a frame is to broadcast it, thus the UL frame rate limit is similar to a broadcast rate limit.)
In addition to the previously mentioned STP protection measures and storm control options, access security, port security, and MAC filtering rules can be applied on the TL-SG2216. Access to the configuration of the switch is controlled by user name and password. Users can have either admin or guest access, and you can set rules that define the source IP addresses, MAC addresses, and ports that can have access to the configuration of the switch.
Port security is configured by applying MAC address limits. Although the TL-SG2216 has a limit of 8000 MAC addresses in its MAC table, you can restrict the number of MAC addresses that can be learned on a port. This feature can prevent someone from plugging in another switch and connecting excessive or unapproved devices to the network.
Port security is disabled on all ports by default on the TL-SG2216. A maximum number of learned MAC addresses can be specified per port, along with choosing a learning mode by port. Learning modes are dynamic, static and permanent. Dynamic MAC address learning is standard switch behavior, static MAC address learning means that MAC addresses stays in memory even if the device disconnects, until the switch is rebooted or the MAC address is deleted. Permanent MAC address learning is the same as static, but permanently learned MAC addresses can only be manually deleted.
Finally, security rules in the form of MAC filtering can be applied. Traffic to and from specific MAC addresses can be blocked by creating a MAC filtering rule. In the below screenshot, I created a basic filtering rule to block traffic to and from MAC address 00-1c-23-01-02-03. I set up a continuous ping to the device with this MAC, and watched the ping succeed without the rule and fail with the rule implemented, validating the TL-SG2216's MAC filtering capability.
TP-LINK TL-SG2216 MAC address filtering
Jumbo frames are enabled by default on the TL-SG2216 and cannot be disabled. The switch passes frames up to 10k bytes in size. My PC can only generate up to 4k byte frames and I had no problem passing 4k byte frames through the TL-SG2216.
In addition to the features discussed, the TL-SG2216 has options for port mirroring, SNMP, Multicast, sys logging, basic diagnostic tools (ping, traceroute, cable test), administrative tools (config backup, resetting and rebooting the device) and a display of traffic statistics by port.
I find port mirroring is a useful tool to examine traffic to and from a specific device or port. Below I created a simple rule to copy all ingress and egress traffic from port 8 and send it to port 16. With this rule in place and Wireshark running on my PC connected to port 16, I was able to examine all traffic going to and from port 8.
TP-LINK TL-SG2216 port mirroring
Finally, the TL-SG2216's traffic summary page has a nice display of inbound and outbound traffic volumes measured in bytes and octets as shown in the screenshot below.
TP-LINK TL-SG2216 traffic statistics
I put together Table 2 of Layer 2 Gigabit smart switches along with a couple of key specs on each switch. The specs in the below table are from the product specifications page on each manufacturer's website. The prices are from Pricegrabber.com, snapshotted near the end of November, 2012.
|Make and Model||RJ45 ports||SFP ports||MAC addresses||Backplane (Gbps)||VLANs||Warranty||Price|
|TP-LINK TL-SG2216||16||2||8k||32||512||5 years||$137.95|
|TP-LINK TL-SG2424||24||4||8k||48||512||5 years||$152.95|
|Cisco SG200-18||18||2||8k||32||256||Limited Lifetime||$254.99|
|Cisco SG200-26||26||2||8k||52||256||Limited Lifetime||$266.40|
Table 2: Product comparison
All of these switches are fanles /silent and configured via a web GUI. In my experience, all three manufacturers do a good job with VLANs and basic layer 2 switching functionality. There are few feature differences between the switches, such as the Cisco switches support IPv6, the NETGEAR and Cisco switches offer “Green Ethernet” for power saving and the TP-LINK supports more VLANs.
I think two key things stand out when you look at Table 2—warranties and price. TP-LINK has a 5 year warranty, Cisco offers a limited lifetime warranty (the power supply is only covered for one year) and NETGEAR offers the highest protection of a lifetime warranty. Price, however, is where the TP-LINK shines. TP-LINK's 16 port switch is $137 while its 24 port TL-SG2424 sibling is $152. In contrast, both Cisco and NETGEAR's switches are over $200. That's a big difference.
From a feature standpoint, I was impressed with the TL-SG2216. I had no problems configuring and using its features. It appears to me that TP-LINK is trying to become one of the top three networking brands in the world by undercutting the competition via price, while providing comparable features. In my opinion, the TL-SG2216 will help them toward that goal!