Draft: draft-ietf-detnet-tsn-vpn-over-mpls

Commentary: Adding conformance language and packet processing details .
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Class of Service.
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Multi-Segment PseudoWire (MS-PW).
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Packet Elimination Function.
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Packet Replication Function.
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Packet Ordering Function.
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Packet Switched Network.
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Quality of Service.
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The sub-sections describe procedures for forwarding packets by DetNet
Edge nodes, where such packets are received from either directly
connected CEs (TSN nodes) or some other DetNet Edge nodes.
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TSN specific functions are executed on the data received by the PE
from the CE before presentation to the DetNet PW for transmission
across the DetNet domain, or on the data received from a DetNet PW by
a PE before it is output on the Attachment Circuit (AC).
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TSN specific functions are executed on the data received by the
DetNet Edge Node from the connected CE before forwarded to connected
CE(s) or presentation to the DetNet Service Proxy function for
transmission across the DetNet domain, or on the data received from a
DetNet PW by a PE before it is output on the Attachment Circuit(s)
(AC).
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When a PE receives a packet from a CE, on a given AC with DetNet
service, it MUST first check via Stream Identification whether the
packet belongs to a configured TSN Stream (i.e., App-flow from DetNet
perspective).  If no Stream ID is matched and no other (VPN) service
is configured for the AC then packet MUST be dropped.  If there is a
matching TSN Stream then the Stream-ID specific TSN functions MUST be
executed (e.g., ingress policing, header field manipulation in case
of active Stream Identification, FRER, etc.).  Source MAC lookup MAY
also be used for local MAC address learning.
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If the PE decides to forward the packet, the packet MUST be forwarded
according to the TSN Stream specific configuration to connected CE(s)
(in case of local bridging) and/or to the DetNet Service Proxy (in
case of forwarding to remote CE(s) required).  If there are no TSN
Stream specific forwarding configurations the PE MUST flood the
packet to other locally attached CE(s) and to the DetNet Service
Proxy.  If the administrative policy on the PE does not allow
flooding the PE MUST drop the packet.
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When a TSN entity of the PE receives a packet from the DetNet Service
Proxy, it MUST first check via Stream Identification whether the
packet belongs to a configured TSN Stream.  If no Stream ID is
matched then packet MUST be dropped.  If there is a matching TSN
Stream then the Stream ID specific TSN functions MUST be executed
(e.g., header field manipulation in case of active Stream
Identification, FRER, etc.).  Source MAC lookup MAY also be used for
local MAC address learning.
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If the PE decides to forward the packet, the packet MUST be forwarded
according to the TSN Stream specific configuration to connected
CE(s).  If there are no TSN Stream specific forwarding configurations
the PE MUST flood the packet to locally attached CE(s).  If the
administrative policy on the PE does not allow flooding the PE MUST
drop the packet.
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The Service Proxy function maps between App-flows and DetNet flows.
The DetNet Edge Node TSN function MUST support the TSN Stream
identification functions and the related managed objects as defined
in IEEE8021CB and IEEEP8021CBdb to recognize the App-flow related
packets.  The Service Proxy presents TSN Streams as an App-flow to a
DetNet Flow.
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The Service Proxy function maps between App-flows and DetNet flows.
The DetNet Edge Node TSN entity MUST support the TSN Stream
identification functions and the related managed objects as defined
in IEEE8021CB and IEEEP8021CBdb to recognize the App-flow related
packets.  The Service Proxy presents TSN Streams as an App-flow to a
DetNet Flow.
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When a DetNet Service Proxy receives a packet from the TSN Entity it
MUST check whether such an App-flow is present in its mapping table.
If present it associates the internal DetNet flow-ID to the packet
and MUST forward it to the DetNet Service and Forwarding sub-layers.
If no matching statement is present it MUST drop the packet.
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When a DetNet Service Proxy receives a packet from the DetNet Service
and Forwarding sub-layers it MUST be forwarded to the Edge Node TSN
Entity.
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The LSP used to forward the DetNet packet may be of any type (MPLS-
LDP, MPLS-TE, MPLS-TP RFC5921, or MPLS-SR I-D.ietf-spring-segment-
routing-mpls).  The LSP (F-Label) label and/or the S-Label may be
used to indicate the queue processing as well as the forwarding
parameters.
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For further details see I-D.ietf-detnet-mpls.
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The LSP used to forward the DetNet packet may be of any type (MPLS-
LDP, MPLS-TE, MPLS-TP RFC5921, or MPLS-SR RFC8660).  The LSP
(F-Label) label and/or the S-Label may be used to indicate the queue
processing as well as the forwarding parameters.
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When a PE receives a packet from the Service Proxy function it MUST
add to the packet the DetNet flow-ID specific S-label and create a
d-CW.  The PE MUST forward the packet according to the configured
DetNet Service and Forwarding sub-layer rules to other PE nodes.
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When a PE receives an MPLS packet from a remote PE, then, after
processing the MPLS label stack, if the top MPLS label ends up being
a DetNet S-label that was advertised by this node, then the PE MUST
forward the packet according to the configured DetNet Service and
Forwarding sub-layer rules to other PE nodes or via the Detnet
Service Proxy function towards locally connected CE(s).
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For further details on DetNet Service and Forwarding sub-layers see
I-D.ietf-detnet-mpls.