User`s guide

Configuring WAN Connections
Nailed groups
Pipeline User’s Guide Preliminary January 30, 1998 1-3
Nailed groups
A nailed connection is a permanent, physical circuit that is always up as long as
the physical connection persists. (A nailed connection can also be a permanent
virtual circuit, which is not a single physical connection, but a dedicated,
switched link.) If the unit or central switch resets or if the link is terminated for
any reason, the Pipeline attempts to restore the link at 10-second intervals. If the
Pipeline or the far-end unit is powered off, the link is restored when power is
restored.
On an ISDN line, a nailed connection uses only one B channel. Each B channel
can be connected to a different leased line to a different destination. A Frame
Relay link is not channelized and is always 100% nailed up.
MPP
(includes
MP+)
Multichannel Point-to-Point Protocol (MPP), Multilink Protocol
Plus (MP+), and Bandwidth Allocation Control Protocol (BACP)
are all enhancements to PPP for supporting multi-channel links.
(MP+ is an implementation of MPP developed by Ascend
Communications, Inc.)
If a connection is set up for MPP, the Pipeline first requests MP+.
If the other side of the connection doesn’t support MP+, the
Pipeline requests MP. If that protocol is refused, PPP is used
instead. That is why the term “PPP connection” is often used to
mean any one of these encapsulation methods when the number of
channels is not relevant.
Frame
Relay
The Frame Relay RFC 1490 standard does not support
authentication.
A Frame Relay gateway connection supports routing and bridging
to and from the switch across a nailed connection.
Some Ascend units provide Frame Relay operations as a software
option.
Method Connection description and attributes