rfc9815v4.txt | rfc9815.txt | |||
---|---|---|---|---|
skipping to change at line 95 ¶ | skipping to change at line 95 ¶ | |||
6.2. Dual-Stack Support | 6.2. Dual-Stack Support | |||
6.3. SPF Calculation Based on BGP-LS-SPF NLRI | 6.3. SPF Calculation Based on BGP-LS-SPF NLRI | |||
6.4. IPv4/IPv6 Unicast Address Family Interaction | 6.4. IPv4/IPv6 Unicast Address Family Interaction | |||
6.5. NLRI Advertisement | 6.5. NLRI Advertisement | |||
6.5.1. Link/Prefix Failure Convergence | 6.5.1. Link/Prefix Failure Convergence | |||
6.5.2. Node Failure Convergence | 6.5.2. Node Failure Convergence | |||
7. Error Handling | 7. Error Handling | |||
7.1. Processing of BGP-LS-SPF TLVs | 7.1. Processing of BGP-LS-SPF TLVs | |||
7.2. Processing of BGP-LS-SPF NLRIs | 7.2. Processing of BGP-LS-SPF NLRIs | |||
7.3. Processing of BGP-LS Attributes | 7.3. Processing of BGP-LS Attributes | |||
7.4. BGP-LS-SPF Link State NLRI Database Synchronization | 7.4. BGP-LS-SPF Link State Database Synchronization | |||
8. IANA Considerations | 8. IANA Considerations | |||
8.1. BGP-LS-SPF Allocation in the SAFI Values Registry | 8.1. BGP-LS-SPF Allocation in the SAFI Values Registry | |||
8.2. BGP-LS-SPF Assignments in the BGP-LS NLRI and Attribute | 8.2. BGP-LS-SPF Assignments in the BGP-LS NLRI and Attribute | |||
TLVs Registry | TLVs Registry | |||
8.3. BGP-LS-SPF Node NLRI Attribute SPF Status TLV Values | 8.3. BGP-LS-SPF Node NLRI Attribute SPF Status TLV Values | |||
Registry | Registry | |||
8.4. BGP-LS-SPF Link NLRI Attribute SPF Status TLV Values | 8.4. BGP-LS-SPF Link NLRI Attribute SPF Status TLV Values | |||
Registry | Registry | |||
8.5. BGP-LS-SPF Prefix NLRI Attribute SPF Status TLV Values | 8.5. BGP-LS-SPF Prefix NLRI Attribute SPF Status TLV Values | |||
Registry | Registry | |||
skipping to change at line 193 ¶ | skipping to change at line 193 ¶ | |||
BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all | BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all | |||
capitals, as shown here. | capitals, as shown here. | |||
1.3. BGP Shortest Path First (SPF) Motivation | 1.3. BGP Shortest Path First (SPF) Motivation | |||
Given that [RFC7938] already describes how BGP could be used as the | Given that [RFC7938] already describes how BGP could be used as the | |||
sole routing protocol in an MSDC, one might question the motivation | sole routing protocol in an MSDC, one might question the motivation | |||
for defining an alternative BGP deployment model when a mature | for defining an alternative BGP deployment model when a mature | |||
solution exists. For both alternatives, BGP offers the operational | solution exists. For both alternatives, BGP offers the operational | |||
benefits of a single routing protocol as opposed to the combination | benefits of a single routing protocol as opposed to the combination | |||
of IGP for the underlay and BGP as the overlay. However, BGP SPF | of an IGP for the underlay and BGP as the overlay. However, BGP SPF | |||
offers some unique advantages above and beyond standard BGP path- | offers some unique advantages above and beyond standard BGP path- | |||
vector routing. With BGP SPF, the simple single-hop peering model | vector routing. With BGP SPF, the simple single-hop peering model | |||
recommended in Section 5.2.1 of [RFC7938] is augmented with peering | recommended in Section 5.2.1 of [RFC7938] is augmented with peering | |||
models requiring fewer BGP sessions. | models requiring fewer BGP sessions. | |||
A primary advantage is that all BGP speakers in the BGP SPF routing | A primary advantage is that all BGP speakers in the BGP SPF routing | |||
domain have a complete view of the topology. This allows support for | domain have a complete view of the topology. This allows support for | |||
ECMP, IP fast-reroute (e.g., Loop-Free Alternatives (LFAs) [RFC5286], | ECMP, IP fast-reroute (e.g., Loop-Free Alternatives (LFAs) [RFC5286], | |||
Shared Risk Link Groups (SRLGs) [RFC4202], and other routing | Shared Risk Link Groups (SRLGs) [RFC4202], and other routing | |||
enhancements without advertisement of additional BGP paths [RFC7911] | enhancements without advertisement of additional BGP paths [RFC7911] | |||
skipping to change at line 280 ¶ | skipping to change at line 280 ¶ | |||
encodings that are no longer applicable. Unless explicitly specified | encodings that are no longer applicable. Unless explicitly specified | |||
in the context of BGP SPF, all optional path attributes SHOULD NOT be | in the context of BGP SPF, all optional path attributes SHOULD NOT be | |||
advertised. If received, all path attributes MUST be accepted, | advertised. If received, all path attributes MUST be accepted, | |||
validated, and propagated consistently with the BGP protocol | validated, and propagated consistently with the BGP protocol | |||
[RFC4271], even if not needed by BGP SPF. | [RFC4271], even if not needed by BGP SPF. | |||
Section 9.1 of [RFC4271] defines the Decision Process that is used to | Section 9.1 of [RFC4271] defines the Decision Process that is used to | |||
select routes for subsequent advertisement by applying the policies | select routes for subsequent advertisement by applying the policies | |||
in the local Policy Information Base (PIB) to the routes stored in | in the local Policy Information Base (PIB) to the routes stored in | |||
its Adj-RIBs-In. The output of the Decision Process is the set of | its Adj-RIBs-In. The output of the Decision Process is the set of | |||
routes that are announced by a BGP speaker to its peers. These | routes that is announced by a BGP speaker to its peers. These | |||
selected routes are stored by a BGP speaker in the speaker's Adj- | selected routes are stored by a BGP speaker in the speaker's Adj- | |||
RIBs-Out, according to policy. | RIBs-Out, according to policy. | |||
The BGP SPF extension fundamentally changes the Decision Process, as | The BGP SPF extension fundamentally changes the Decision Process, as | |||
described herein. Specifically: | described herein. Specifically: | |||
1. BGP advertisements are readvertised to neighbors immediately | 1. BGP advertisements are readvertised to neighbors immediately | |||
without waiting or dependence on the route computation, as | without waiting or dependence on the route computation, as | |||
specified in phase 3 of the base BGP Decision Process. Multiple | specified in phase 3 of the base BGP Decision Process. Multiple | |||
peering models are supported, as specified in Section 4. | peering models are supported, as specified in Section 4. | |||
skipping to change at line 445 ¶ | skipping to change at line 445 ¶ | |||
SPF route calculation. All the other TLVs are considered as optional | SPF route calculation. All the other TLVs are considered as optional | |||
TLVs. Documents specifying usage of optional TLVs for BGP SPF MUST | TLVs. Documents specifying usage of optional TLVs for BGP SPF MUST | |||
address backward compatibility. | address backward compatibility. | |||
5.1.2. BGP-LS Attribute | 5.1.2. BGP-LS Attribute | |||
The BGP-LS Attribute of the BGP-LS-SPF SAFI uses the exact same | The BGP-LS Attribute of the BGP-LS-SPF SAFI uses the exact same | |||
format as the BGP-LS AFI [RFC9552]. In other words, all the TLVs | format as the BGP-LS AFI [RFC9552]. In other words, all the TLVs | |||
used in the BGP-LS Attribute of the BGP-LS AFI are applicable and are | used in the BGP-LS Attribute of the BGP-LS AFI are applicable and are | |||
used for the BGP-LS Attribute of the BGP-LS-SPF SAFI. This attribute | used for the BGP-LS Attribute of the BGP-LS-SPF SAFI. This attribute | |||
is an optional, non-transitive BGP attribute that is used to carry | is an optional, non-transitive BGP attribute that is used to | |||
link, node, and prefix properties and attributes. The BGP-LS | advertise link, node, and prefix properties and attributes. The BGP- | |||
Attribute is a set of TLVs. | LS Attribute is a set of TLVs. | |||
All the TLVs defined for the BGP-LS Attribute [RFC9552] are | All the TLVs defined for the BGP-LS Attribute [RFC9552] are | |||
applicable and can be used with the BGP-LS-SPF SAFI to carry link, | applicable and can be used with the BGP-LS-SPF SAFI to advertise | |||
node, and prefix properties and attributes. | link, node, and prefix properties and attributes. | |||
The BGP-LS Attribute may potentially be quite large depending on the | The BGP-LS Attribute may potentially be quite large depending on the | |||
amount of link-state information associated with a single BGP-LS-SPF | amount of link-state information associated with a single BGP-LS-SPF | |||
NLRI. The BGP specification [RFC4271] mandates a maximum BGP message | NLRI. The BGP specification [RFC4271] mandates a maximum BGP message | |||
size of 4096 octets. It is RECOMMENDED that an implementation | size of 4096 octets. It is RECOMMENDED that an implementation | |||
support [RFC8654] in order to accommodate a greater amount of | support [RFC8654] in order to accommodate a greater amount of | |||
information within the BGP-LS Attribute. BGP speakers MUST ensure | information within the BGP-LS Attribute. BGP speakers MUST ensure | |||
that they limit the TLVs included in the BGP-LS Attribute to ensure | that they limit the TLVs included in the BGP-LS Attribute to ensure | |||
that a BGP UPDATE message for a single BGP-LS-SPF NLRI does not cross | that a BGP UPDATE message for a single BGP-LS-SPF NLRI does not cross | |||
the maximum limit for a BGP message. The determination of the types | the maximum limit for a BGP message. The determination of the types | |||
skipping to change at line 578 ¶ | skipping to change at line 578 ¶ | |||
presence of parallel unnumbered links. | presence of parallel unnumbered links. | |||
The link descriptors are described in Table 4 of [RFC9552]. | The link descriptors are described in Table 4 of [RFC9552]. | |||
Additionally, the Address Family (AF) Link Descriptor TLV is defined | Additionally, the Address Family (AF) Link Descriptor TLV is defined | |||
to determine whether an unnumbered link can be used in the IPv4 SPF, | to determine whether an unnumbered link can be used in the IPv4 SPF, | |||
the IPv6, or both (refer to Section 5.2.2.1). | the IPv6, or both (refer to Section 5.2.2.1). | |||
For a link to be used in SPF computation for a given address family, | For a link to be used in SPF computation for a given address family, | |||
i.e., IPv4 or IPv6, both routers connecting the link MUST have | i.e., IPv4 or IPv6, both routers connecting the link MUST have | |||
matching addresses (i.e., router interface addresses must be on the | matching addresses (i.e., router interface addresses must be on the | |||
same subnet for numbered interfaces, and the Link Local/Remote | same subnet for numbered interfaces, or the Link Local/Remote | |||
Identifiers (Section 6.3) must match for unnumbered interfaces). | Identifiers (Section 6.3) must match for unnumbered interfaces). | |||
The IGP Metric (TLV 1095) MUST be advertised. If a BGP speaker | The IGP Metric (TLV 1095) MUST be advertised. If a BGP speaker | |||
receives a Link NLRI without an IGP Metric attribute TLV, then it | receives a Link NLRI without an IGP Metric attribute TLV, then it | |||
MUST consider the received NLRI as malformed (refer to Section 7). | MUST consider the received NLRI as malformed and is handled as | |||
The BGP SPF metric length is 4 octets. A metric is associated with | described in Section 7.1. The BGP SPF metric length is 4 octets. A | |||
the output side of each router interface. This metric is | metric is associated with the output side of each router interface. | |||
configurable by the system administrator. The lower the metric, the | This metric is configurable by the system administrator. The lower | |||
more likely the interface is to be used to forward data traffic. One | the metric, the more likely the interface is to be used to forward | |||
possible default for the metric would be to give each interface a | data traffic. One possible default for the metric would be to give | |||
metric of 1 making it effectively a hop count. | each interface a metric of 1 making the SPF metric effectively a hop | |||
count. | ||||
The usage of other link attribute TLVs is beyond the scope of this | The usage of other link attribute TLVs is beyond the scope of this | |||
document. | document. | |||
5.2.2.1. BGP-LS Link NLRI Address Family Link Descriptor TLV | 5.2.2.1. BGP-LS Link NLRI Address Family Link Descriptor TLV | |||
For unnumbered links, the address family cannot be ascertained from | For unnumbered links, the address family cannot be ascertained from | |||
the endpoint link descriptors. Hence, the Address Family Link | the endpoint link descriptors. Hence, the Address Family Link | |||
Descriptor TLV SHOULD be included with the Link Local/Remote | Descriptor TLV SHOULD be included with the Link Local/Remote | |||
Identifiers TLV for unnumbered links, so that the link can be used in | Identifiers TLV for unnumbered links, so that the link can be used in | |||
skipping to change at line 775 ¶ | skipping to change at line 776 ¶ | |||
When incrementing the sequence number for each self-originated NLRI, | When incrementing the sequence number for each self-originated NLRI, | |||
the sequence number should be treated as an unsigned 64-bit value. | the sequence number should be treated as an unsigned 64-bit value. | |||
If the lower-order 32-bit value wraps, the higher-order 32-bit value | If the lower-order 32-bit value wraps, the higher-order 32-bit value | |||
should be incremented and saved in non-volatile storage. If a BGP | should be incremented and saved in non-volatile storage. If a BGP | |||
speaker completely loses its sequence number state (e.g., the BGP | speaker completely loses its sequence number state (e.g., the BGP | |||
speaker hardware is replaced or experiences a cold start), the BGP | speaker hardware is replaced or experiences a cold start), the BGP | |||
NLRI selection rules (see Section 6.1) ensure convergence, albeit not | NLRI selection rules (see Section 6.1) ensure convergence, albeit not | |||
immediately. | immediately. | |||
If the Sequence Number TLV is not received, then the corresponding | If the Sequence Number TLV is not received, then the corresponding | |||
NLRI is considered as malformed and MUST be handled as 'treat-as- | NLRI is considered as malformed and MUST be handled as described in | |||
withdraw'. An implementation SHOULD log an error for further | Section 7.1. An implementation SHOULD log an error for further | |||
analysis. | analysis. | |||
5.3. BGP-LS-SPF End of RIB (EoR) Marker | 5.3. BGP-LS-SPF End of RIB (EoR) Marker | |||
The usage of the EoR marker [RFC4724] with the BGP-LS-SPF SAFI is | The usage of the EoR marker [RFC4724] with the BGP-LS-SPF SAFI is | |||
somewhat different than the other BGP SAFIs. Reception of the EoR | somewhat different than the other BGP SAFIs. Reception of the EoR | |||
marker MAY optionally be expected prior to advertising a Link NLRI | marker MAY optionally be expected prior to advertising a Link NLRI | |||
for a given peer. | for a given peer. | |||
5.4. BGP Next-Hop Information | 5.4. BGP Next-Hop Information | |||
skipping to change at line 956 ¶ | skipping to change at line 957 ¶ | |||
prefixes (both IPv4 and IPv6) as well as BGP-LS-SPF node | prefixes (both IPv4 and IPv6) as well as BGP-LS-SPF node | |||
reachability. Implementations may choose to implement this with | reachability. Implementations may choose to implement this with | |||
separate RIBs for each address family and/or separate RIBs for | separate RIBs for each address family and/or separate RIBs for | |||
prefix and node reachability. | prefix and node reachability. | |||
Global Routing Information Base (GLOBAL-RIB): The RIB containing the | Global Routing Information Base (GLOBAL-RIB): The RIB containing the | |||
current routes that are installed in the router's forwarding | current routes that are installed in the router's forwarding | |||
plane. This is commonly referred to in networking parlance as | plane. This is commonly referred to in networking parlance as | |||
"the RIB". | "the RIB". | |||
Link State NLRI Database (LSNDB): A database of BGP-LS-SPF NLRIs | Link State Database (LSDB): A database of BGP-LS-SPF NLRIs that | |||
that facilitate access to all Node, Link, and Prefix NLRIs. | facilitate access to all Node, Link, and Prefix NLRIs. | |||
Candidate List (CAN-LIST): A list of candidate Node NLRIs used | Candidate List (CAN-LIST): A list of candidate Node NLRIs used | |||
during the BGP SPF calculation. The list is sorted by the cost to | during the BGP SPF calculation. The list is sorted by the cost to | |||
reach the Node NLRI, with the Node NLRI that has the lowest | reach the Node NLRI, with the Node NLRI that has the lowest | |||
reachability cost at the head of the list. This facilitates the | reachability cost at the head of the list. This facilitates the | |||
execution of the Dijkstra algorithm, where the shortest paths | execution of the Dijkstra algorithm, where the shortest paths | |||
between the local node and other nodes in the graph are computed. | between the local node and other nodes in the graph are computed. | |||
The CAN-LIST is typically implemented as a heap but other data | The CAN-LIST is typically implemented as a heap but other data | |||
structures have been used. | structures have been used. | |||
skipping to change at line 1159 ¶ | skipping to change at line 1160 ¶ | |||
6.4. IPv4/IPv6 Unicast Address Family Interaction | 6.4. IPv4/IPv6 Unicast Address Family Interaction | |||
While the BGP-LS-SPF address family and the BGP unicast address | While the BGP-LS-SPF address family and the BGP unicast address | |||
families may install routes into the routing tables of the same | families may install routes into the routing tables of the same | |||
device, they operate independently (i.e., "ships-in-the-night" mode). | device, they operate independently (i.e., "ships-in-the-night" mode). | |||
There is no implicit route redistribution between the BGP-LS-SPF | There is no implicit route redistribution between the BGP-LS-SPF | |||
address family and the BGP unicast address families. | address family and the BGP unicast address families. | |||
It is RECOMMENDED that BGP-LS-SPF IPv4/IPv6 route computation and | It is RECOMMENDED that BGP-LS-SPF IPv4/IPv6 route computation and | |||
installation be given scheduling priority by default over other BGP | installation be given scheduling priority by default over other BGP | |||
address families as these address families are considered as underlay | address families as the BGP-LS-SPF SAFI is considered an underlay | |||
SAFIs. | SAFI. | |||
6.5. NLRI Advertisement | 6.5. NLRI Advertisement | |||
6.5.1. Link/Prefix Failure Convergence | 6.5.1. Link/Prefix Failure Convergence | |||
A local failure prevents a link from being used in the SPF | A local failure prevents a link from being used in the SPF | |||
calculation due to the IGP bidirectional connectivity requirement. | calculation due to the IGP bidirectional connectivity requirement. | |||
Consequently, local link failures SHOULD always be communicated as | Consequently, local link failures SHOULD always be communicated as | |||
quickly as possible and given priority over other categories of | quickly as possible and given priority over other categories of | |||
changes to ensure expeditious propagation and optimal convergence. | changes to ensure expeditious propagation and optimal convergence. | |||
According to standard BGP procedures, the link would continue to be | According to standard BGP procedures, the link would continue to be | |||
used until the last copy of the BGP-LS-SPF Link NLRI is withdrawn. | used until the last copy of the BGP-LS-SPF Link NLRI is withdrawn. | |||
In order to avoid this delay, the originator of the Link NLRI SHOULD | In order to avoid this delay, the originator of the Link NLRI SHOULD | |||
advertise a more recent version with an increased Sequence Number TLV | advertise a more recent version with an increased Sequence Number TLV | |||
for the BGP-LS-SPF Link NLRI including the SPF Status TLV (refer to | for the BGP-LS-SPF Link NLRI including the SPF Status TLV (refer to | |||
Section 5.2.2.2) indicating the link is down with respect to BGP SPF. | Section 5.2.2.2) indicating the link is down with respect to BGP SPF. | |||
The configurable LinkStatusDownAdvertise timer controls the interval | The configurable LinkStatusDownAdvertise timer controls the interval | |||
that the BGP-LS-LINK NLRI is advertised with SPF Status indicating | that the BGP-LS-SPF Link NLRI is advertised with SPF Status | |||
the link is down prior to withdrawal. If the BGP-LS-SPF Link NLRI is | indicating the link is down prior to withdrawal. If the BGP-LS-SPF | |||
advertised with the SPF Status TLV included in the BGP-LS Attribute, | Link NLRI is advertised with the SPF Status TLV included in the BGP- | |||
and the link becomes available in that period, the originator of the | LS Attribute, and the link becomes available in that period, the | |||
BGP-LS-SPF Link NLRI MUST advertise a more recent version of the BGP- | originator of the BGP-LS-SPF Link NLRI MUST advertise a more recent | |||
LS-SPF Link NLRI without the SPF Status TLV in the BGP-LS Link | version of the BGP-LS-SPF Link NLRI without the SPF Status TLV in the | |||
Attribute. The suggested default value for the | BGP-LS Link Attribute. The suggested default value for the | |||
LinkStatusDownAdvertise timer is 2 seconds. | LinkStatusDownAdvertise timer is 2 seconds. | |||
Similarly, when a prefix becomes unreachable, a more recent version | Similarly, when a prefix becomes unreachable, a more recent version | |||
of the BGP-LS-SPF Prefix NLRI SHOULD be advertised with the SPF | of the BGP-LS-SPF Prefix NLRI SHOULD be advertised with the SPF | |||
Status TLV (refer to Section 5.2.3.1) to indicate that the prefix is | Status TLV (refer to Section 5.2.3.1) to indicate that the prefix is | |||
unreachable in the BGP-LS Prefix Attributes, and the prefix will be | unreachable in the BGP-LS Prefix Attributes, and the prefix will be | |||
considered unreachable with respect to BGP SPF. The configurable | considered unreachable with respect to BGP SPF. The configurable | |||
PrefixStatusDownAdvertise timer controls the interval that the BGP- | PrefixStatusDownAdvertise timer controls the interval that the BGP- | |||
LS-Prefix NLRI is advertised with SPF Status indicating the prefix is | LS-Prefix NLRI is advertised with SPF Status indicating the prefix is | |||
unreachable prior to withdrawal. If the BGP-LS-SPF Prefix has been | unreachable prior to withdrawal. If the BGP-LS-SPF Prefix has been | |||
skipping to change at line 1209 ¶ | skipping to change at line 1210 ¶ | |||
the SPF Status TLV in the BGP-LS Prefix Attributes. The suggested | the SPF Status TLV in the BGP-LS Prefix Attributes. The suggested | |||
default value for the PrefixStatusDownAdvertise timer is 2 seconds. | default value for the PrefixStatusDownAdvertise timer is 2 seconds. | |||
6.5.2. Node Failure Convergence | 6.5.2. Node Failure Convergence | |||
By default, all the NLRIs advertised by a node are withdrawn when a | By default, all the NLRIs advertised by a node are withdrawn when a | |||
session failure is detected [RFC4271]. If fast failure detection | session failure is detected [RFC4271]. If fast failure detection | |||
such as BFD [RFC5880] is utilized, and the node is on the fastest | such as BFD [RFC5880] is utilized, and the node is on the fastest | |||
converging path, the most recent versions of BGP-LS-SPF NLRI will be | converging path, the most recent versions of BGP-LS-SPF NLRI will be | |||
withdrawn. This may result in older versions of NLRIs received from | withdrawn. This may result in older versions of NLRIs received from | |||
one or more peers on a different path(s) in the LSNDB until they are | one or more peers on a different path(s) in the LSDB until they are | |||
withdrawn. These stale NLRIs will not delay convergence since the | withdrawn. These stale NLRIs will not delay convergence since the | |||
adjacent nodes detect the link failure and advertise a more recent | adjacent nodes detect the link failure and advertise a more recent | |||
NLRI indicating the link is down with respect to BGP SPF (refer to | NLRI indicating the link is down with respect to BGP SPF (refer to | |||
Section 6.5.1) and the bidirectional connectivity check fails during | Section 6.5.1) and the bidirectional connectivity check fails during | |||
the BGP SPF calculation (refer to Section 6.3). | the BGP SPF calculation (refer to Section 6.3). | |||
7. Error Handling | 7. Error Handling | |||
This section describes error-handling actions, as described in | This section describes error-handling actions, as described in | |||
[RFC7606], that are specific to BGP-LS-SPF SAFI BGP UPDATE message | [RFC7606], that are specific to BGP-LS-SPF SAFI BGP UPDATE message | |||
skipping to change at line 1292 ¶ | skipping to change at line 1293 ¶ | |||
BGP speaker MUST handle such a malformed NLRI as 'treat-as-withdraw' | BGP speaker MUST handle such a malformed NLRI as 'treat-as-withdraw' | |||
[RFC7606]. | [RFC7606]. | |||
When a BGP speaker receives a BGP Update that does not contain any | When a BGP speaker receives a BGP Update that does not contain any | |||
BGP-LS Attributes, it is most likely an indication of 'Attribute | BGP-LS Attributes, it is most likely an indication of 'Attribute | |||
Discard' fault handling, and the BGP speaker SHOULD preserve and | Discard' fault handling, and the BGP speaker SHOULD preserve and | |||
propagate the BGP-LS-SPF NLRI as described in Section 8.2.2 of | propagate the BGP-LS-SPF NLRI as described in Section 8.2.2 of | |||
[RFC9552]. However, NLRIs without the BGP-LS Attribute MUST NOT be | [RFC9552]. However, NLRIs without the BGP-LS Attribute MUST NOT be | |||
used in the SPF calculation (Section 6.3). How this is accomplished | used in the SPF calculation (Section 6.3). How this is accomplished | |||
is an implementation matter, but one way would be for these NLRIs not | is an implementation matter, but one way would be for these NLRIs not | |||
to be returned in LSNDB lookups. | to be returned in LSDB lookups. | |||
7.2. Processing of BGP-LS-SPF NLRIs | 7.2. Processing of BGP-LS-SPF NLRIs | |||
A BGP speaker supporting the BGP-LS-SPF SAFI MUST perform the | A BGP speaker supporting the BGP-LS-SPF SAFI MUST perform the | |||
syntactic validation checks of the BGP-LS-SPF NLRI listed in | syntactic validation checks of the BGP-LS-SPF NLRI listed in | |||
Section 8.2.2 of [RFC9552] to determine if it is malformed. | Section 8.2.2 of [RFC9552] to determine if it is malformed. | |||
7.3. Processing of BGP-LS Attributes | 7.3. Processing of BGP-LS Attributes | |||
A BGP speaker supporting the BGP-LS-SPF SAFI MUST perform the | A BGP speaker supporting the BGP-LS-SPF SAFI MUST perform the | |||
syntactic validation checks of the BGP-LS Attribute listed in | syntactic validation checks of the BGP-LS Attribute listed in | |||
Section 8.2.2 of [RFC9552] to determine if it is malformed. | Section 8.2.2 of [RFC9552] to determine if it is malformed. | |||
An implementation SHOULD log an error for further analysis for | An implementation SHOULD log an error for further analysis for | |||
problems detected during syntax validation. | problems detected during syntax validation. | |||
7.4. BGP-LS-SPF Link State NLRI Database Synchronization | 7.4. BGP-LS-SPF Link State Database Synchronization | |||
While uncommon, there may be situations where the LSNDBs of two BGP | While uncommon, there may be situations where the LSDBs of two BGP | |||
speakers support the BGP-LS-SPF SAFI lose synchronization. In these | speakers support the BGP-LS-SPF SAFI lose synchronization. In these | |||
situations, the BGP session MUST be reset unless other means of | situations, the BGP session MUST be reset unless other means of | |||
resynchronization are used (beyond the scope of this document). When | resynchronization are used (beyond the scope of this document). When | |||
the session is reset, the BGP speaker MUST send a NOTIFICATION | the session is reset, the BGP speaker MUST send a NOTIFICATION | |||
message with the BGP error code "Loss of LSDB Synchronization" as | message with the BGP error code "Loss of LSDB Synchronization" as | |||
described in Section 3 of [RFC4271]. The mechanisms to detect loss | described in Section 3 of [RFC4271]. The mechanisms to detect loss | |||
of synchronization are beyond the scope of this document. | of synchronization are beyond the scope of this document. | |||
8. IANA Considerations | 8. IANA Considerations | |||
End of changes. 15 change blocks. | ||||
33 lines changed or deleted | 34 lines changed or added | |||
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