RADIUS

Name

NAS-Port-Type

Synopsis

Attribute Number	61
Length	6
Value	ENUM
Allowed in	Access-Request
Prohibited in	Access-Accept, Access-Reject, Access-Challenge
Presence in Packet	Required, unless NAS-Port is present
Maximum Iterations	1

The enumerated value in this attribute depicts what kind of NAS port to which the user has connected. There are 20 physical port types, which are listed in Table 3-5.

Table 3-5. NAS-Port-Type attribute values

Value	Type of port
0	Asynchronous
1	Synchronous
2	ISDN Synchronous
3	ISDN Asynchronous V.120
4	ISDN Asynchronous V.110
5	Virtual
6	PIAFS
7	HDLC Clear Channel
8	X.25
9	X.75
10	G.3 Fax
11	SDSL
12	ADSL-CAP
13	ADSL-DMT
14	IDSL
15	Ethernet
16	XDSL
17	Cable
18	Wireless other
19	Wireless CCITT 802.11

This list of ports covers almost all of the types that would be used in practice. For clarification, I’ll discuss a few of the different options that are more commonly found in everyday use:

Asynchronous connections (0)

The most common type of port used for dial-up clients.

Synchronous (2) connections

ISDN clients most often use this connection, but they may also use two flavors of asynchronous (3 and 4) connections as well.

PIAFS (6), or PHS Internet Access Forum Standard

A protocol used primarily in Japan to allow access to devices such as digital cameras, connection concentrators, cellular and mobile telephones, and other handy devices.

Symmetric DSL (11), asymmetric DSL (12 and 13), and DSL over ...