Operations, Administration, and Maintenance for MPLS-SR over IP
ZTE Corp.
gregimirsky@gmail.com
Routing
MPLS Working Group
Internet-Draft
OAM
MPLS-SR
Segment routing uses source routing paradigm to traffic engineering by specifying segments a packet traverses through the network.
MPLS Segment Routing applies that paradigm to an MPLS data plane-based networks. SR-MPLS over IP
uses MPLS label stack as a source routing instruction set and uses IP encapsulation/tunneling such as MPLS-in-
UDP as defined in RFC 7510 to realize a source routing mechanism across MPLS,
IPv4, and IPv6 data planes. This document describes Operations, Administration, and Maintenance
operations in SR-MPLS over IP environment.
Segment routing uses source routing paradigm to traffic
engineering by specifying segments a packet traverses through the network.
MPLS Segment Routing (SR-MPLS) applies
that paradigm to an MPLS data plane-based networks. SR-MPLS over IP
uses MPLS label stack as a source routing instruction set and uses IP encapsulation/tunneling such as MPLS-in-
UDP as defined in to realize a source routing mechanism across MPLS,
IPv4, and IPv6 data planes. This document describes Operations, Administration, and Maintenance (OAM)
operations in SR-MPLS over IP environment.
MPLS: Multiprotocol Label Switching
LSP: Label Switched Path
BFD: Bidirectional Forwarding Detection
SR Segment Routing
SR-MPLS Segment Routing in MPLS data plane
FEC: Forwarding Equivalence Class
G-ACh: Generic Associated Channel
ACH: Associated Channel Header
GAL: G-ACh Label
OAM Operations, Administration, and Maintenance
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
when, and only when, they appear in all capitals, as shown here.
OAM operations support Fault Management and Performance Monitoring components of FCAPS framework for network management.
To achieve its objectives, Fault Management OAM includes proactive and on-demand protocols to provide constant monitoring of the network to
detect the failure in combination with on-demand tools to efficiently localize and characterize the defect. Performance Monitoring OAM protocols support
measurement of packet loss and packet delay that enables calculation of performance metrics, e.g., packet loss ration, inter-packet delay variation,
that are useful in monitoring the quality of service in the network, detect and quantify the service degradation.
Fault management OAM toolset includes protocols to perform on-demand failure detection and localization as well as
proactively monitor path continuity. An example of the former is echo request/reply, e.g., Label Switched Path (LSP) Ping .
An example of the latter - Bidirectional Forwarding Detection (BFD) over MPLS LSP . For SR-MPLS environment
applicability and use of these OAM tools defined in and respectively. Both
LSP Ping and BFD can be used either with IP/UDP encapsulation or in Generic Associated Channel (G-ACh) . The use of
IP/UDP encapsulation is well-understood and has been defined in :
The IP header is set as
follows: the source IP address is a routable address of the sender;
the destination IP address is a (randomly chosen) IPv4 address from
the range 127/8 or an IPv6 address from the range
0:0:0:0:0:FFFF:7F00:0/104. The IP TTL is set to 1. The source UDP
port is chosen by the sender.
Using the sender's routable address enables the receiver to send
an echo reply or BFD control packets over the IP network.
In some environments, the overhead of
extra IP/UDP encapsulations may be considered as overburden and make to use more compact G-ACh encapsulation instead.
In such a case, the OAM control packet MUST be immediately followed by the
IP Address TLV with its Value field containing
one of the routable IP addresses of the sender.
Performance monitoring in SR-MPLS over IP may be performed using mechanisms defined in .
This document does not introduce new security aspects but inherits all security considerations
from , , ,
.