Extreme Networks Summit WM20, Руководство пользователя

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Discovery and Registration Overview
Summit WM20 User Guide, Software Release 4.2
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Wireless AP Discovery
Wireless APs discover the IP address of a Summit WM Controller using a sequence of mechanisms that
allow for the possible services available on the enterprise network. The discovery process is successful
when the Wireless AP successfully locates a Summit WM Controller to which it can register.
You must ensure that the appropriate services on your enterprise network are prepared to support the
discovery process. The following five steps summarize the discovery process:
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Step 1 – Use the IP address of the last successful connection to a Summit WM Controller.
Once a Wireless AP has successfully registered with a Summit WM Controller, it recalls that
controller's IP address, and uses that address on subsequent reboots. The AP bypasses discovery and
goes straight to registration. If this discovery method fails, it cycles through the remaining steps until
successful.
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Step 2 – Use the predefined static IP addresses for the Summit WM Controllers on the network (if
configured).
You can specify a list of static IP addresses of the Summit WM Controllers on your network. On the
Static Configuration tab, add the addresses to the Summit Switch Search List .
CAUTION
Wireless APs configured with a static Summit Switch Search List can only connect to Summit WM Controllers in the
list. Improperly configured Wireless APs cannot connect to a non-existent Summit WM Controller address, and
therefore cannot receive a corrected configuration.
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Step 3 – Use Dynamic Host Configuration Protocol (DHCP) Option 78 to locate a Service Location
Protocol (SLP) Directory Agent (DA), followed by a unicast SLP request to the Directory Agent.
To use the DHCP and unicast SLP discovery method, you must ensure that the DHCP server on
your network supports Option 78 (DHCP for SLP RFC2610). The Wireless APs use this method to
discover the Summit WM Controller.
This solution takes advantage of two services that are present on most networks:
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DHCP (Dynamic Host Configuration Protocol) – The standard means of providing IP addresses
dynamically to devices on a network.
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SLP (Service Location Protocol) – A means of allowing client applications to discover network
services without knowing their location beforehand. Devices advertise their services using a
Service Agent (SA). In larger installations, a Directory Agent (DA) collects information from SAs
and creates a central repository (SLP RFC2608).
The Summit WM Controller contains an SLP SA that, when started, queries the DHCP server for
Option 78 and if found, registers itself with the DA as service type Extreme. The Summit WM
Controller contains a DA (slpd).
The Wireless AP queries DHCP servers for Option 78 in order to locate any DAs. The Wireless APs
SLP User Agent then queries the DAs for a list of Extreme Networks SAs.
Option 78 must be set for the subnets connected to the ports of the Summit WM Controller and the
subnets connected to the Wireless APs. These subnets must contain an identical list of DA IP
addresses.
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Step 4 – Use a Domain Name Server (DNS) lookup for the host name Controller.domain-name.
If no DA is found, or if it has no Extreme Networks SAs registered, the Wireless AP attempts to
locate a Summit WM Controller via DNS.
If you use this method for discovery, place an A record in the DNS server for Controller.<domain-
name>. The <domain-name> is optional, but if used, ensure it is listed with the DHCP server.