SNAX/XF and SNAX/APN Configuration and Management Manual

Configuring for Token-Ring Support
SNAX/XF and SNAX/APN Configuration and Management Manual—425836-006
9-9
The IEEE Specifications
The IEEE has also defined an internetworking and network management standard
(802.1), and a logical link control standard (802.2).
HP’s support for Token-Ring is primarily concerned with LLC (802.2) and Token-Ring
(802.5) standards.
The (802.2) LLC Services
The LLC layer is involved with links between network entities; in the case of
Token-Ring, these are links between stations on the ring. There are three key LLC
services:

The LLC layer allows different types of conversation to take place on the ring.
These conversation types are related to the amount of error detection, frame
sequencing and flow control required by the user application. For details, see
Types of Conversation on page 9-15.

The LLC layer organizes the physical network node into multiple logical network
entities (service access points, or SAPs) for program communication—essentially
providing an entry point from the ring to any number of different higher-level
protocol stacks—for example, SNA, Internet, or NetBIOS stacks. For details, see
SAPs and Link Station Addresses on page 9-12.

The LLC layer provides a single frame type, the Link Protocol Data Unit (LPDU),
that is encapsulated in the MAC data frame. For details, see Description of Frames
on page 9-15 and Figure 9-11 on page 9-17.
The (802.5) Token-Ring MAC Services
The MAC services defined by IEEE 802.5 govern the generation and use of the token
as a method of access control. The MAC layer is also responsible for the management
of the ring through MAC frames.
For further details on management issues at the MAC services level, see the PAM
Programming Manual.