BIT INDEX EXPLICIT REPLICATION TREE TRACE OPERATION ADMINISTRATION AND MAINTENANCE USING PROXY MODE
Publication Date: 2015-Nov-30
The IP.com Prior Art Database
Gaofeng Tao: AUTHOR [+7]
Mechanisms and systems are provided to trace multiple Bit Forwarding Egress Routers BFERs of a Bit Index Explicit Replication BIER architecture in which multicast data packets are forwarded This allows detecting all Equal Cost Multi Paths ECMPs for a plurality of BFERs in the BIER architecture In addition failures such as black holes and data plane control plane inconsistencies ECMP inconsistencies in the BIER architecture can be detected The techniques described herein use a proxy mode to relay an echo request packet from node hop to node instead of using Time to Live TTL techniques
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BIT INDEX EXPLICIT REPLICATION TREE TRACE OPERATION, ADMINISTRATION AND MAINTENANCE USING PROXY MODE
Carlos M. Pignataro
Nagendra Kumar Nainar Samuel Liu
Alan Xiao-Rong Wang
CISCO SYSTEMS, INC.
Mechanisms and systems are provided to trace multiple Bit-Forwarding Egress Routers (BFERs) of a Bit Index Explicit Replication (BIER) architecture in which multicast data packets are forwarded. This allows detecting all Equal-Cost Multi Paths (ECMPs) for a plurality of BFERs in the BIER architecture. In addition, failures, such as "black holes," and data plane/control plane inconsistencies (ECMP inconsistencies) in the BIER architecture can be detected. The techniques described herein use a proxy mode to relay an echo request packet from node (hop) to node instead of using Time to Live (TTL) techniques.
Bit Index Explicit Replication (BIER) is an architecture that provides optimal multicast forwarding through a "BIER domain" without requiring intermediate routers to maintain any multicast related per-flow state. Conventional Operation, Administration and Maintenance (OAM) procedures can only trace one BFER at a time. The conventional procedures do not allow tracing multiple BFERs at a time, and there is no easy way to detect the topology of the BIER domain. As a result, in order to trace multiple BFERs or to detect the topology of the BIER domain, conventional procedures require tracing each BFER separately and to repeat the trace multiple times.
Copyright 2015 Cisco Systems, Inc.
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By using a stateless multipoint replication approach as described in detail below, multiple BFERs can be traced at one time. This new approach improves BIER OAM scalability and is easy to use.
Existing approaches define a basic BIER OAM packet format and a procedure to support ECMP path discovery between a Bit Forwarding Ingress Router (BFIR) and a given BFER. The BFIR specifies a particular single BFER and uses a TTL mechanism in which a BIER Multi-Protocol Label Switched (MPLS) label TTL value is set and repeatedly incremented for packets sent to traceroute the particular BFER.
The BIER OAM packet header format that follows a BIER header is defined as follows:
Ver Message Type Proto
Message Type Dependent Data
Two message types are possible, namely "BIER Echo Request" and "BIER Echo Reply."
The Echo Request/Reply header format is defined as follows:
Ver Echo Req/Rep Proto
QTF RTF Reply mode Return Code Return Subcode
The basic BIER OAM packet format can be used to perform failure detection and failure isolation on the BIER data plane.
FIG. 1 illustrates a BIER network with multiple equal cost paths.
Copyright 2015 Cisco Systems, Inc.
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As shown in FIG. 1, the BIER network includes multiple nodes including BFIR A and BFERs G and H.