DLEP Lantency Range
ExtensionLincoln LaboratoryMassachusetts Institute of Technology244 Wood StreetLexingtonMA02420-9108bcheng@ll.mit.eduLabN Consulting, L.L.C.lberger@labn.net
This document defines an extension to the DLEP protocol to provide the
range of latency that may be experienced on a link.
The Dynamic Link Event Protocol (DLEP) is defined in . It provides the exchange of link
related control information between DLEP peers. DLEP peers are
comprised of a modem and a router. DLEP defines a base set of
mechanisms as well as support for possible extensions. This
document defines one such extension.
The base DLEP specification includes the Latency metric which provides
an average latency on a link. This document adds the ability to relay
the minimum and maximum latency range seen on a link. The extension
defined in this document is referred to as "Latency Range".
This document defines a new DLEP Extension Type Value in which is used to indicate the use of the
extension, and one new DLEP Data Items in .
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14, RFC 2119 .
The use of the Latency Range Extension SHOULD be configurable. To
indicate that the Latency Range Extension is to be used, an
implementation MUST include the Latency Range Extension Type Value in
the Extensions Supported Data Item. The Extensions Supported Data
Item is sent and processed according to .
The Latency Range Extension Type Value is TBA1, see .
The Latency Range Data Item serves much the same purpose as the
Latency Data Item defined in with
the addition of being able to communicate the latency range that may
be experienced by traffic on a link. The Latency Range Item MAY be
carried in the same messages and MUST be processed according to the
same rules as the Latency Range Data Item defined in .
The format of the Latency Range Data Item is:
TBA216
A 64-bit unsigned integer, representing the transmission longest
delay, in microseconds, that a packet encounters as it is
transmitted over the link.
A 64-bit unsigned integer, representing the transmission shortest
delay, in microseconds, that a packet encounters as it is
transmitted over the link.
The extension introduces a new mechanism for flow control between a
router and modem using the DLEP protocol. The
extension does not inherently introduce any additional threats
above those documented in .
The approach taken to Security in that document applies equally
when running the extension defined in this document.
This document requests the assignment of 2 values by IANA. All
assignments are to registries defined by .
This document requests one new assignment to the DLEP Extensions
Registry named "Extension Tyoe Values" in the range with the
"Specification Required" policy. The requested value is as follows:
CodeDescriptionTBA1Latency Range
This document requests one new assignment to the DLEP Data Item
Registry named "Data Item Values" in the range with the "Specification
Required" policy. The requested values are as follows:
Type CodeDescriptionTBA2Latency Range