The “P” in the SG500-28P model name means it supports Power over Ethernet (PoE). PoE is used frequently with VoIP devices, providing power over the network cable and eliminating the need for a separate power cable and outlet for the PoE end device.
The SG500-28P supports PoE standards 802.3af and the newer 802.3at. The SG500-28P can provide a maximum of 180W of power on ports 1-26. As a simple test, I plugged in a Grandstream PoE device to a port, saw it get power and boot immediately. You can see that port 7 is drawing 7600mW in Figure 13.
Figure 13: PoE port status
The SG500-28P is an advanced stackable switch with a massive array of features. You can check out a complete list of features on Cisco's small business 500 series switches is available in the 500 Series Data Sheet. Here's a rundown of a few other key features:
- “Smartports” on the SG500 are statically or dynamically customized ports configured via Link Layer Discovery Protocol (LLDP) or Cisco Discovery Protocol (CDP) for specific device types, such as printers, PCs, VoIP devices, network devices, and so on.
- Port mirroring can be applied by port or by VLAN, enabling packet captures and advanced troubleshooting of network devices.
- The SG500's “Green Ethernet” feature will temporary disable a port when it becomes inactive, and reduce power on ports connected to short Ethernet cables (less than 50m).
- More complex features on the SG500 include an array of options to manage Multicast traffic, as well as detailed support for SNMP communication with network monitoring systems.
To understand how Cisco's small business switch series vary in performance, I looked at Cisco 24 port Gigabit capable switches in the 100, 200, 300, and 500 series.
Note, the Cisco 24 port 200-500 series switches may have up to 28 ports counting combo and stacking ports. A combo port is actually two physical ports, one copper and one fiber, with the fiber port supporting a fiber connector. If both the copper and fiber port in the pair are connected, the fiber port will be active. A stacking port is used for connecting, or stacking, multiple switches together. Also, I added the SG500X-24P to the comparison to include Cisco's fastest switch in the small business series.
The performance and capacity data in Table 3 are from Cisco's website and pricing is from Pricegrabber.com. Switching capacity, measured in Gigabits per second (Gbps), is the size of the data bus on the switch, which is a physical component rating. Forwarding capacity, measured in millions of 64-byte packets per second (mpps), is the speed of the packet processor, which is a throughput rating.
Table 3: Cisco switch comparison
As you can see in Table 3, as the model numbers go up, so does switching and forwarding capacity. MAC table capacity and the number of supported VLANs increase from the 100 to the 300 series, but are the same in the 300 and 500 series. Obviously, price goes up as you add capacity, speed, and functionality.
So, which Cisco small business switch is the ideal switch for your network? I recommend starting by evaluating the number of ports and port speed required. If you need a simple "dumb" switch, the 100 series fits that bill. If you need VLANs, port mirroring or other simple managed switch features, you need at least the 200 series.
If you need your VLANs to live on different subnets, you need the Layer 3 functionality of the 300 series. If you need routing on the switch, you need the Layer 3 functionality of the 300 series. Finally, if you're looking to consolidate management of multiple switches with stacking, or need 5 or 10 Gigabit Ethernet uplinks, the 500 series is for you.
It's hard to compare apples to apples when you compare different switch manufacturers, as different manufacturers bundle features differently. For example, the Cisco SG500 Series Stackable Managed switches seem to fall between NETGEAR's ProSafe Stackable Smart switches and NETGEAR's ProSafe Stackable Managed switches, as shown in Table 4.
|Model||Switching Capacity (Gbps)||MAC table size||VLAN||PoE||Price|
Table 4: NETGEAR, Cisco switch comparison
Interestingly, the Cisco switch sits in the middle of the two NETGEAR switches in terms of switching capacity and price, yet has a larger MAC table and supports more VLANs than either NETGEAR.
Comparisons to NETGEAR aside, with the Cisco SG500-28P you get a high speed switch with 24 Gigabit Ethernet ports, 4 Gigabit Ethernet expansion ports (2 "combo" Gigabit Ethernet plus 2 1GE/5GE SFP), VLAN and Layer 3 functionality, and the ability to combine multiple switches into an easier to manage switch “stack.”
You also get support for network protocols and services including LLDP, CDP, STP, RSTP, MSTP, IPv6, TACACS+, RADIUS, 802.1x, ACLs, 802.1p, SNMP and a price around $950. With all these features, the SG500-28P is a high performance switch for a substantial network!