HP Vm200 User Manual

							Creating WDS links
Key concepts
8-3
Simultaneous access point and WDS support
The V-M200 can be configured to simultaneously support wireless communities and one or 
more WDS links. Although this offers flexibility, it does have the following limitations:
The total available bandwidth on the radio is shared between all WDS links and wireless 
users. This can result in reduced throughput if lots of traffic is being sent by both wireless 
users and the WDS links. You can use the QoS feature to prioritize traffic. See Quality of 
service (QoS) on page 4-15 for details.
The same radio options are used for both wireless clients and WDS links.
Using the 5 GHz band for WDS links
It is recommended that 802.11n or 802.11a in the 5 GHz band be used for WDS links whenever 
possible. This optimizes throughput and reduces the potential for interference.
Advantages
Most Wi-Fi clients support 802.11b or b/g, therefore most APs are set to operate in the 2.4 
GHz band. This frees the 5 GHz band for other applications such as WDS.
802.11a and 802.11n channels in the 5 GHz band are non-overlapping.
Assuming an optimal implementation, 802.11a supports up to 54 Mbps and 802.11n 
supports up to 300 Mbps, providing a fat pipe for traffic exchange.
Limitations
WDS links are not supported when the radio is configured in one of the following 
compatibility modes: 802.11n/a, 802.11n/g, or 802.11n/b/g. Since the same radio 
options must be used for both wireless clients and WDS links, support for 802.11b/g 
clients is not possible.
The 5 GHz band has a shorter reach when compared to the 2.4 GHz band. This could be a 
factor depending on the distance your WDS link span.
Quality of service
The WDS feature enables you to define a quality of service (QoS) setting that will govern how 
traffic is sent on all WDS links. 
The QoS feature defines four traffic queues based on the Wi-Fi Multimedia (WMM) access 
categories. In order of priority, these queues are: 
QueueWMM access categoryTy p i c a l l y  u s e d  f o r
1
2
3
4AC_VO
AC_VI
AC_BE
AC_BKVoice traffic
Video traffic
Best effort data traffic
Background data traffic 
						

							Creating WDS links
Key concepts
8-4
Traffic on a WDS link is assigned to a queue based on the selected priority mechanism. Traffic 
delivery is based on strict priority (per the WMM standard). Therefore, if excessive traffic is 
present on queues 1 or 2, it will reduce the flow of traffic on queues 3 and 4. 
Regardless of the priority mechanism that is selected, traffic that cannot be classified by a 
priority mechanism is assigned to queue 3.
NoteWhen traffic is forwarded onto a WDS link from a wireless community, the QoS settings of 
the community take priority. For example, if you create a wireless community with a QoS 
setting of Community Based High, then traffic from this community will traverse the WDS 
link on queue 2, even if the QoS setting on the WDS link is Low (queue 4). 
Priority mechanisms
Priority mechanisms are used to classify wireless community traffic and assign it to the 
appropriate queue. The following mechanisms are available:
802.1p
This mechanism classifies traffic based on the value of the VLAN priority field present within 
the VLAN header.
Very High, High, Normal, Low
These mechanisms enable you to assign a specific priority level to all traffic.
Queue802.1p (VLAN priority field value)
16, 7
24 ,5
30, 3
41, 2
QueuePriority value
1 Very High
2High
3Normal
4Low 
						

							Creating WDS links
Key concepts
8-5
Diffserv (Differentiated Services)
This mechanism classifies traffic based on the value of the Differentiated Services (DS) 
codepoint field in IPv4 and IPv6 packet headers (as defined in RFC2474). The codepoint is 
composed of the six most significant bits of the DS field. 
Spanning-tree protocol
The Spanning-Tree Protocol (STP) can be used to prevent undesirable loops from occurring 
in the network that may result in decreased throughput. To enable STP for wireless links, see 
Bridge spanning tree protocol on page 6-9.
Discovery protocols
The V-M200 supports the Link Layer Discovery Protocol (LLDP) and the Cisco Discovery 
Protocol (CDP). These protocols provide a mechanism for the V-M200 to exchange 
information about its identity, capabilities, and interconnection with other devices on the 
network. When enabled, both protocols function across an active WDS links. See Discovery 
protocols on page 6-7.
Configuration considerations
The following guidelines apply when you create a WDS link between two or more V-M200s.
All radios must be set to the same operating frequency and channel. This means that on 
the Wireless > Radio page under Channel, you cannot select Automatic.
The Ethernet ports for all V-M200s must be connected to the same subnet, and each 
V-M200 must have a unique IP address.
If AES/CCMP security is enabled, the same key must be defined on all V-M200s.
Although the V-M200 can support up to three WDS links, only one wireless link can be 
defined between any two V-M200s.
QueueDiffServ (DS codepoint value)
1 111000 (Network control)
110000 (Internetwork control)
2 101000 (Critical) 
100000 (Flash override)
3 011000 (Flash)
000100 (Routine)
4 010000 (Immediate)
001000 (Priority) 
						

							Creating WDS links
WDS configuration settings
8-6
WDS configuration settings
To view or add a WDS link, select Wireless > WDS. 
To configure a WDS link, select its name in the list. Or to add a WDS link, select Add WDS 
Link. In either case, the WDS link page opens. 
Settings 
Enabled/Disabled
Specify if the WDS link is enabled or disabled. Once a link is enabled, it actively attempts to 
establish the WDS connection to the remote V-M200. To view the status of the WDS 
connection, select Status > WDS. 
						

							Creating WDS links
Sample WDS deployment
8-7
Name
Name of the WDS link.
Speed
Sets the speed the link will operate at. For load balancing you may want to limit the speed of 
a link when connecting to multiple destinations. 
Select the Auto option to have the V-M200 automatically choose the speed that provides the 
best throughput (least number of errors).
Security
AES/CCMP security
Enables AES with CCMP encryption to secure traffic on the link. The V-M200 uses the key 
you specify in the Key field to generate the keys that encrypt the wireless data stream. 
Specify a key that is between 8 and 63 ASCII characters in length. It is recommended that the 
key be at least 20 characters long and be a mix of letters and numbers.
Addressing
Remote MAC address 
Specify the MAC address of the wireless port on the remote  to which 
this link will connect. The MAC address must be in the following format: 12 hexadecimal 
numbers, with the values “a” to “f” in lowercase. For example: 0003520a0f01.
Local MAC address 
Shows the MAC address of the wireless port on the V-M200. This address needs to be entered 
on the V-M200 to which this link will connect.
Sample WDS deployment
This example shows you how to create a wireless link between two physically separate 
network segments. 
This example assumes that both V-M200s have their IP addresses set and are connected to 
their respective networks as shown in the diagram.
DHCP server
Wireless link
WDSV-M200
#1V-M200
#2
192.168.5.10 192.168.5.20
5.1
5.155.165.21 5.22 
						

							Creating WDS links
Sample WDS deployment
8-8
A.Obtain the MAC address of V-M200 #2
1.Connect to the management tool on V-M200 #2. Open the home page and write down its 
MAC address.
B.Setup the WDS link on V-M200 #1
2.Open the management tool on V-M200 #1.
3.Select Wireless > Radio. The Radio configuration page opens.
Enable the Radio.
Set Operating mode to Access point and WDS bridge.
Set Wireless mode to 802.11n (5 GHz).
Set Channel to Channel 36.
Select Save.
4.Select Wireless > WDS. 
  
						

							Creating WDS links
Sample WDS deployment
8-9
5.Select Add WDS Link.
Under Security:
Enable security.
Set Key to a39xm2.
Under Addressing:
Set Remote MAC address to the MAC address of V-M200 #2.
Select Save.
 
C.Setup the WDS link on V-M200 #2
Configuration settings on V-M200 #2 are similar to those defined on V-M200 #1.
1.Open the management tool on the V-M200 #2.
2.Select Wireless > Radio. The Radio configuration page opens.
Enable the Radio.
Set Operating mode to Access point and WDS bridge.
Set Wireless mode to 802.11n (5 GHz).
Set Channel to Channel 36.
Select Save.
3.Select Wireless > WDS.  
						

							Creating WDS links
Sample WDS deployment
8-10
4.Select Add WDS Link.
Under Security:
Enable AES/CCMP security.
Set Key to a39xm2.
Under Addressing:
Set Remote MAC address to the MAC address of V-M200 #2.
Select Save.
D.Test the link and make performance adjustments
The WDS link should now be active. 
1.Select To o l s  >  P i n g on V-M200 #1 and ping the address of V-M200 #2 (192.168.5.20). If the 
ping succeeds, it means that the WDS link is working.
2.Select Status > WDS. The WDS status page opens.
3.Select WDS link in the table. The WDS link status page opens.
4.Use the SNR value as a guide to adjust the antennas to obtain the best possible Tx Rate. 
A higher SNR value means a better quality radio link. 
After each change, allow a minimum of two minutes for Tx Rate to report its new value. 
						

							Chapter 9: Maintenance
9
Maintenance
Contents
Config file management............................................................................................... 9-2
Backup configuration............................................................................................ 9-2
Restore configuration ........................................................................................... 9-2
Reset configuration ............................................................................................... 9-3
Software updates.......................................................................................................... 9-3 
						

							Maintenance
Config file management
9-2
Config file management
The configuration file contains all the settings that customize the operation of the V-M200. 
You can save and restore the configuration file by selecting Maintenance > Config file 
management.
Backup configuration
The Backup configuration feature enables you to back up your configuration settings so 
that they can be easily restored in case of failure. 
Before you install new software, you should always back up your current configuration. 
Select Backup to start the process. You are prompted for the location in which to save the 
configuration file.
NoteThe local username and password for the manager and operator accounts are not saved to 
the backup configuration file. If you restore a configuration file, the current manager and 
operator username and password are not overwritten.
Restore configuration
The Restore configuration feature enables you to load a previously saved configuration 
file. Use the following steps to restore a saved configuration file.
1.Select Maintenance > Config file management. The Config file management page 
opens.