Multi-Path
Concurrent Measurement for IPPMHuaweiBeijingChinadangjuanna@huawei.comChina TelecomBeijingChinawangjl50@chinatelecom.cnLG U+SeoulKorealeesy@lguplus.co.krThis test method can test multi-paths concurrently from one edge node
to another edge node. This document details Multi-Path Concurrent
Measurement (MPCM).As we know, the current network has been already being in load
balancing mode, however it is partially congested. In other words, from
the same source node to the same destination node, some paths have been
congested to cause a decline in service quality, but some paths carry
less traffic and are lightly loaded. To solve the problem of unbalanced
network load, the first is to have the
ability to detect the quality of the load sharing paths. And then the
traffic from the Scr node to the Dst node is required to be steered from
the congested paths into the lightly loaded path/paths basing on the
SLA's requirement. So it's necessary to measure the multi-paths in
load-balancing mode.In the traditional method, the paths are measured separately because
they aren't maintained by the path group. If the multiple load sharing
paths are required to be selected based on the SLA information, the
measured SLA information needs to be comparable. If you want to ensure
that the data obtained by the test is available and accurate, the
multi-paths are required to maintain by the path group in order that the
test start and end points must be same.For example, the low latency services require millisecond delays. If
the start time and the end time aren't same, the measured data may not
be in one test cycle, and the accuracy of this data is relatively low
and the data cannot be compared.The Multi-Path Concurrent Measurement (MPCM) is required, which can
be used bi-directionally to concurrently measure multi-paths metrics
between two network elements. At the same time, this method also
consider saving the number of test messages to reduces the load on the
network.The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119.Muti-pathsThere are multiple paths between two nodes in the network.
These paths may be equal-cost multi-path (ECMP) mode or
unequal-cost multiple (UCMP) mode. In a real network, they
might be one or tunnel group.ConcurrentIn order to ensure comparability between multiple paths,
the test start point and the test end point are required to be
same.The Multi-Path Concurrent Measurement (MPCM) is the way of
measurement of multi-paths metrics.MPCM can be embedded into a variety of transports such as NSH,
Segment Routing, VxLAN, native IPv6 (via extension header), or IPv4.This section defines path header and associated data types required
for MPCM.Firstly one path packet format of
multi-path can be defined.Session ID: A set of load sharing pathsPath ID: One path of the session.Path-E2E-Type: A 16-bit identifier which Indicates whether the
packet type is a send message or a request message.Flags: 8-bit field. Identify the query or response type.
Following flags are defined: Bit 0 Identify the query typeBit 1 Identify the response typeReservedTransaction ID: 16-bit identifier of one measurement transaction.
The sender and receiver to identify measurement transactions based
on Transaction ID.When a measurement is for a set of paths, each query message is
made for each path, but only one unified response message replies.The measurement response packet format of a path is as
follows.The field of PathN Edge-to-Edge Option Data can refer to Edge-to-Edge
Option Data of .It suppose there are N paths between two points.The measurement
response packet format of multi-paths is as follows.Long-term measurementThe receiver can wait until it receives all measurement
requests of a set of path and then responds.Short-term measurementThe Sender can query once t.The receiver can reply once t.The overall solution needs to consider two methods of
long-period measurement and short-period measurement.The measurement message format defined by this document can be
extended based on various measurement methods.A new type may be added in IOAM-E2E-Type of IOAM Edge-to-Edge
Option header
as follow.Bit 4: Multiple paths measurement.This bit is set by the headend node if Multi-Path Concurrent
Measurement is activated.A common registry is maintained for IOAM-Types, see .For path-based quality measurements, there is no need to measure
each message because the large-scale deployment consumes too much
network resources. Here, the way of periodic measurement is
recommended.In a period, if there is a packet, the appropriate packet
is selected to be inserted into the iOAM packet; if there is no
packet, a measurement packet is directly generated.MPCM nodes collect information for packets traversing a domain that
supports MPCM. MPCM process the information further and export the
information using e.g., IPFIX. Raw data export of IOAM data using IPFIX
is discussed in .This document requests the following IANA Actions.IOAM E2E Type Registry:Bit 4 Multiple ways measurementThe Proof of Transit option (Section Section 4.3 In-situ OAM ) is used for
verifying the path of data packets.TBDA Variety of TransportsIOAM Edge-to-Edge OptionSegment Routing Policy ArchitectureVirtual eXtensible Local Area Network (VXLAN)In-situ OAM raw data export with IPFIXInstant Congestion Assessment Network (iCAN) for Traffic
EngineeringA One-Path Congestion Metric for IPPM