For the Wireless AP’s process to "discover" the HiPath Wireless Controller, the Controller, Access Points and Convergence Software system relies on a DHCP server that supports Option 78 and 79 for Service Location Protocol (SLP). The combination of Dynamic Host Configuration Protocol (DHCP), Option 78 and 79, and SLP provide a technique that defines the HiPath Wireless Controller as the only element on the network that the Wireless AP can communicate with.
Option 78 is a list of IP addresses of Directory Agents, used by Service Agents and Users Agents.
For the purposes of the Controller, Access Points and Convergence Software system, Option 78 should be set to the IP address of the HiPath Wireless Controller management port. The HiPath Wireless Controller will run the SLP daemon and act as a directory service.
Option 79 is an identifier that refers to a set of services called a "scope". If a User Agent has been assigned to a scope, it can only see the services in that scope. This will limit the IP addresses of Directory Agents available to the User Agent.
Here's how Controller, Access Points and Convergence Software uses these SLP options:
1. The HiPath Wireless Controller Manager or the Wireless AP Manager use the Service Agent:
● to look up the location of the Directory Agent using Option 78 and 79 in the DHCP server
● to register with the Directory Agent
2. The Wireless AP User Agent looks up the location of the Directory Agent using Option 78 and 79 in the DHCP server.
3. The Wireless AP User Agent contacts the Directory Agent for services of the types
"Chantry".
4. The Wireless AP attempts to connect with the HiPath Wireless Controller or Wireless AP Manager.
Now the use of SLP is completed and the Wireless AP and HiPath Wireless Controller will now communicate using a UDP-based tunneling protocol.
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One of the ethernet ports on the HiPath Wireless Controller should be set to allow management traffic so that SLP messages can arrive on that port.Service Location Protocol (SLP) (RFC2608)
C.1 Service Location Protocol (SLP) (RFC2608)
Service Location Protocol (RFC2608) is a method of organizing and locating the resources (such as printers, disk drives, databases, e-mail directories, and schedulers) in a network.
Using SLP, networking applications can discover the existence, location and configuration of networked devices.
In larger installations, services will register their services with one or more Directory Agents, and clients will contact the Directory Agent to fulfill requests for Service Location information.
Service Location Protocol consists of three cooperating services:
● User Agent (UA): A process working on the user's behalf to acquire service attributes and configuration. The User Agent retrieves service information from the Service Agents or Directory Agents.
● Service Agent (SA): A process working on the behalf of one or more services to advertise service attributes and configuration.
● Directory Agent (DA): A process which collects information from Service Agents to provide a single repository of service information in order to centralize it for efficient access by User Agents. There can only be one DA present per given host.
When a service starts on the network, its Service Agent will query the DHCP server for Option 78 and 79 and will register itself appropriately.
C.2 DHCP Options for Service Location Protocol (RFC2610)
The Dynamic Host Configuration Protocol (RFC2131) provides a framework for passing configuration information to hosts on a TCP/IP network.Entities using the Service Location Protocol, Version 2 (RFC2608) and Service Location Protocol, Version 1 (RFC2165) need to obtain the address of Directory Agents in order to transact messages. The SLP Directory Agent option described below (Option 78) is used to configure User Agents and Service Agents with the location of Directory Agents in the network.
The SLP Scope Option (Option 79) provides an assignment of scope for configuration of SLP User and Service Agents. This option takes precedence over both default and static scope configuration of SLP agents. A scope is a set of services, typically making up a logical administrative group.
C.3 SLP Directory Agent Option (Option 78)
The SLP Directory Agent Option 78 specifies a list of IP addresses for SLP Directory Agents.
Directory Agents should be listed in order of preference.
SLP Service Scope Option (Option 79)
The Length value must include one for the 'Mandatory' byte and include four for each Directory Agent address which follows. The address of the Directory Agent is given in network byte order.
The 'Mandatory' byte in the Directory Agent option may be set to either 0 or 1. If it is set to 1, the SLP User Agent or Service Agent so configured must not employ either active or passive multicast discovery of Directory Agents.
The Directory Agents listed in Option 78 must be configured with the a non-empty subset of the scope list that the Agent receiving the Directory Agent Option 78 is configured with.
C.4 SLP Service Scope Option (Option 79)
Services are grouped together using 'scopes'. These are strings that identify a set of services that form an administrative grouping. Service Agents (SAs) and Directory Agents (DAs) are always assigned a scope string.
A User Agent (UA) is normally assigned a scope string (in which case the User Agent will only be able to discover that particular grouping of services). This allows a network administrator to provision services to users. The use of scopes also allows the administrator to scale SLP deployments to larger networks.
The Scope-List String is a comma-delimited list of the scopes that a SLP Agent is configured to use. The Length value must include one for the 'Mandatory' byte.
The 'Mandatory' byte determines whether SLP Agents override their static configuration for scopes with the <Scope List> string provided by the option. This allows DHCP administrators to implement a policy of assigning a set of scopes to Agents for service provision. If the Mandatory byte is 0, static configuration takes precedence over the DHCP provided scope list.
If the Mandatory byte is 1, the <Scope List> provided in this option must be used by the SLP Agent.
The Scope List String usage is defined in the SLPv2 specification (RFC2608).
SLP Service Scope Option (Option 79)
RFC list