Nortel 15000 Terminology page 60

hard rerouting
See connection recovery (page
HDB3
See high-density binary 3 zero maximum encoding (HDB3) (page
HDLC
See high-level data link control (HDLC) (page 61)
HDLC mode
See frame-cell trunk (page
HDLC-transparent data service (HTDS)
A service that transports HDLC-framed data across the network without
interpretation, except that interframe flags are not transmitted. The efficiency
of the transmission is increased by not transmitting flags.
header error control (HEC)
A CRC code found in the last byte of the ATM cell header that is used for
verifying cell integrity.
hello packet
A type of PNNI routing packet that neighboring logical nodes exchange.
Hello protocol
The Hello protocol is a neighbor discovery protocol run over private network-
to-network interface (PNNI) links between lowest level nodes and logical
group nodes (LGNs).
HEP
See hot equipment protection (HEP) (page
HG
See hunt group (HG) (page
hierarchically complete source route
A stack of DTLs that represent a route across a PNNI routing domain. A DTL
is included for each hierarchical level between and including the current level
and the lowest visible level in which the source and destination nodes are
reachable.
high-density binary 3 zero maximum encoding (HDB3)
An encoding technique used to transfer bits over E1 and E3 lines. To ensure
1's density, HDB3 substitutes a bipolar violation where four or more 0s are to
be sent in a row.
Copyright © 2006, Nortel
- 60 -
List of terms
33).
54).
62).
Nortel Multiservice Switch 7400/15000/20000
Terminology
NN10600-005 7.2S1 Standard
PCR7.2 and up March 2006
60).
62).
Nortel Confidential