Network Working Group X. Xu
Internet-Draft Alibaba Inc
Intended status: Standards Track K. Bi
Expires: November 16, 2018 Huawei
J. Tantsura
Nuage Networks
N. Triantafillis
LinkedIn
K. Talaulikar
Cisco
May 15, 2018
BGP Neighbor Autodiscovery
draft-xu-idr-neighbor-autodiscovery-08
Abstract
BGP has been used as the underlay routing protocol in many hyper-
scale data centers. This document proposes a BGP neighbor
autodiscovery mechanism that greatly simplifies BGP deployments.
This mechanism is very useful for those hyper-scale data centers
where BGP is used as the underlay routing protocol.
Requirements Language
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 [RFC2119].
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on November 16, 2018.
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Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. BGP Hello Message Format . . . . . . . . . . . . . . . . . . 3
4. Hello Message Procedure . . . . . . . . . . . . . . . . . . . 10
5. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 11
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 11
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12
7.1. BGP Hello Message . . . . . . . . . . . . . . . . . . . . 12
7.2. TLVs of BGP Hello Message . . . . . . . . . . . . . . . . 12
8. Security Considerations . . . . . . . . . . . . . . . . . . . 12
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 13
9.1. Normative References . . . . . . . . . . . . . . . . . . 13
9.2. Informative References . . . . . . . . . . . . . . . . . 13
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 14
1. Introduction
BGP has been used as the underlay routing protocol instead of IGP in
many hyper-scale data centers [RFC7938]. Furthermore, there is an
ongoing effort to leverage BGP link-state distribution mechanism to
achieve BGP-SPF [I-D.keyupate-lsvr-bgp-spf]. However, BGP is not
good as an IGP from the perspective of deployment automation and
simplicity. For instance, the IP address and the Autonomous System
Number (ASN) of each and every BGP neighbor have to be manually
configured on BGP routers although these BGP peers are directly
connected. Furthermore, for those BGP routers with multiple physical
links being connected, it's usually not ideal to establish BGP
sessions over their directly connected interface addresses because
the BGP update volume would be unnecessarily increased, meanwhile, it
may not be suitable to configure those links as a Link Aggregation
Group (LAG) due to some reasons. As a result, it's more common that
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loopback interface addresses of those directly connected BGP peers
are used for BGP session establishment purpose. To make those
loopback addresses of directly connected BGP peers reachable from one
another, either static routes have to be configured or some kind of
IGP has to be enabled. The former is not good from the network
automation perspective while the latter is not good from the network
simplification perspective (i.e., running less routing protocols).
This draft specifies a BGP neighbor autodiscovery mechanism by
borrowing some ideas from the Label Distribution Protocol (LDP)
[RFC5036] . More specifically, directly connected BGP routers could
automatically discovery each other through the exchange of the to-be-
defined BGP Hello messages. The BGP session establishment process as
defined in [RFC4271] could be triggered once directly connected BGP
neighbors are discovered from one another. Note that the BGP session
should be established over the discovered the peering address of the
BGP neighbor and in most cases the peering address is a loopback
address. In addition, to eliminate the need of configuring static
routes or enabling IGP for the loopback addresses, a certain type of
routes towards the BGP neighbor's loopback addresses as advertised as
peering addresses are dynamically instantiated once the BGP neighbor
has been discovered. The administrative distance of such type of
routes MUST be smaller than their equivalents that are learnt by the
regular BGP update messages . Otherwise, circular dependency would
occur once these loopback addresses are advertised via the regular
BGP updates.
2. Terminology
This memo makes use of the terms defined in [RFC4271].
3. BGP Hello Message Format
To automatically discover directly connected BGP neighbors, a BGP
router periodically sends BGP HELLO messages out those interfaces on
which BGP neighbor autodiscovery are enabled. The BGP HELLO message
MUST sent as a UDP packet with a destination port of TBD (179 is the
preferred port number value) addressed for the "all routers on this
subnet" group multicast address (i.e., 224.0.0.2 in the IPv4 case and
FF02::2 in the IPv6 case). The IP source address is set to the
address of the interface over which the message is sent out.
The HELLO message contains the following fields:
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Version | Type | Message Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AS number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| BGP Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Hold Time | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLVs |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: BGP Hello Message
Version: This 1-octet unsigned integer indicates the protocol
version number of the message. The current BGP version number is
4.
Type: The type of BGP message (Hello - TBD value from BGP Message
Types Registry)
Message Length: This 2-octet unsigned integer specifies the length
in octets of the TLVs field.
AS number: AS Number of the Hello message sender.
BGP Identifier: BGP Identifier of the Hello message sender.
Hold Time: Hello hold timer in seconds. Hello Hold Time specifies
the time the receiving BGP peer will maintain its record of Hellos
from the sending BGP peer without receipt of another Hello. The
RECOMMENDED default value is 15 seconds. A value of 0 means that
the receiving BGP peer should maintain its record until the link
is UP.
Reserved: SHOULD be set to 0 by sender and MUST be ignored by
receiver.
TLVs: This field contains one or more TLVs as described below.
The Accepted ASN List TLV is an optional TLV that is used to signal
the AS numbers from which the router would accept BGP sessions. When
not signaled, it indicates that the router will accept BGP peering
from any ASN from its neighbors. Only a single instance of this TLV
is included and its format is shown below.
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Accepted ASN List(variable) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: Accepted ASN List TLV
Type: TBD1
Length:Specifies the length of the Value field in octets.
Accepted ASN-List: This variable-length field contains one or more
accepted 4-octet ASNs.
The Peering Address TLV is used to indicate to the neighbor the
address to which they should establish BGP session. For each peering
address, the router can specify its supported AFI/SAFI(s). When the
AFI/SAFI values are specified as 0/0, then it indicates that the
neighbor can attempt for negotiation of any AFI/SAFIs. The
indication of AFI/SAFI(s) in the Peering Address TLV is not intended
as an alternative for the MP capabilities negotiation mechanism.
The Peering Address TLV format is shown below and at least one
instance of this TLV MUST be present.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | No. AFI/SAFI | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Address (4-octet or 16-octet) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AFI | SAFI | ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| sub-TLVs ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3: Peering Address TLV
Type: TBD2
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Length:Specifies the length of the Value field in octets.
Flags : Current defined bits are as follows. All other bits
SHOULD be cleared by sender and MUST be ignored by receiver.
Bit 0x1 - address is IPv6 when set and IPv4 when clear
Number of AFI/SAFI: indicates the number of AFI/SAFI pairs that
the router supports on the given peering address.
Reserved: sender SHOULD set to 0 and receiver MUST ignore.
Address: This 4 or 16 octect field indicates the IPv4 or IPv6
address which is used for establishing BGP sessions.
AFI/SAFI : one or more pairs of these values that indicate the
supported capabilities on the peering address.
Sub-TLVs : currently none defined
When the Peering Address used is not the directly connected interface
address (e.g. when it is a loopback address) then local prefix(es)
that cover the peering address(es) MUST be signaled by the router.
This allows the neighbor to learn these local prefix(es) and to
program routes for them over the directly connected interfaces over
which they are being signalled. The Local Prefixes TLV is used to
only signal prefixes that are locally configured on the router and
its format is as shown below.
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| No. of IPv4 Prefixes | No. of IPv6 Prefixes |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 Prefix |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Prefix Mask | ...
+-+-+-+-+-+-+-+-+
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv6 Prefix |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Prefix Mask | ...
+-+-+-+-+-+-+-+-+
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| sub-TLVs ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: Local Prefixes TLV
Type: TBD3
Length:Specifies the length of the Value field in octets
No. of IPv4 Prefixes : specifies the number of IPv4 prefixes.
When value is 0, then it indicates no IPv4 Prefixes are present.
No. of IPv6 Prefixes : specifies the number of IPv6 prefixes.
When value is 0, then it indicates no IPv6 Prefixes are present.
IPv4 Prefix Address & Prefix Mask: Zero or more pairs of IPv4
prefix address and their mask.
IPv6 Prefix Address & Prefix Mask: Zero or more pairs of IPv6
prefix address and their mask.
Sub-TLVs : currently none defined
The Link Attributes TLV is a mandatory TLV that signals to the
neighbor the link attributes of the interface on the local router. A
single instance of this TLV MUST be present in the message. The Link
Attributes TLV is as shown below.
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Local Interface ID | Flags | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| No. of IPv4 Addresses | No. of IPv6 Addresses |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 Local Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Prefix Mask | ...
+-+-+-+-+-+-+-+-+
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv6 Local Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Prefix Mask | ...
+-+-+-+-+-+-+-+-+
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| sub-TLVs ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 5: Link Attributes TLV
Type: TBD4
Length:Specifies the length of the Value field in octets
Local Interface ID : the local interface ID of the interface (e.g.
the MIB-2 ifIndex)
Flags : Currently defined bits are as follows. Other bits SHOULD
be cleared by sender and MUST be ignored by receiver.
Bit 0x1 - indicates link is enabled for IPv4
Bit 0x2 - indicates link is enabled for IPv6
Reserved: SHOULD be set to 0 by sender and MUST be ignored by
receiver.
No. of IPv4 Addresses : specifies the number of IPv4 local
addresses on the interface. When value is 0, then it indicates no
IPv4 Prefixes are present or the interface is IP unnumbered.
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No. of IPv6 Addresses : specifies the number of IPv6 Global
addresses on the interface. When value is 0, then it indicates no
IPv6 Global Prefixes are present or the interface is only
configured with IPv6 link-local addresses
IPv4 Address & Mask: Zero or more pairs of IPv4 address and their
mask.
IPv6 Address & Mask: Zero or more pairs of IPv6 address and their
mask.
Sub-TLVs : currently none defined
The Neighbor TLV is used by a BGP router to indicate the peering
address and information about the neighbors that have been discovered
by the router on the specific link and their status. The BGP session
establishment process begins when both the neighbors accept each
other over at least one underlying inter-connecting link between
them. The Neighbor TLV format is as shown below.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | Status | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Neighbor Peering Address (4-octet or 16-octet) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| sub-TLVs ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 6: Neighbor TLV
Type: TBD5
Length:Specifies the length of the Value field in octets
Flags : Currently defined 0x1 bit is clear when Peering Address is
IPv4 and set when IPv6. Other bits SHOULD be clear by sender and
MUST be ignored by receiver.
Status : Indicates the status code of the peering for the
particular session over this link. The following codes are
currently defined
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0 - Indicates 1-way detection of the peer
1 - Indicates rejection of the peer due to local policy reasons
(i.e. local router would not be initiating or accepting session
to this neighbor)
2 - Indicates 2-way detection of the peering by both neighbors
3 - Indicates that the BGP peering session has been established
between the neighbors and that this link would be utilized for
forwarding to the peer BGP nexthop
Reserved: SHOULD be set to 0 by sender and MUST be ignored by
receiver.
Neighbor Peering Address: This 4 or 16 octect field indicates the
IPv4 or IPv6 peering address of the neighbor for which peering
status is being reported.
Sub-TLVs : currently none defined
4. Hello Message Procedure
A BGP peer receiving Hellos from another peer maintains a Hello
adjacency corresponding to the Hellos. The peer maintains a hold
timer with the Hello adjacency, which it restarts whenever it
receives a Hello that matches the Hello adjacency. If the hold timer
for a Hello adjacency expires the peer discards the Hello adjacency.
We recommend that the interval between Hello transmissions be at most
one third of the Hello hold time.
A BGP session with a peer has one or more Hello adjacencies.
A BGP session has multiple Hello adjacencies when a pair of BGP peers
is connected by multiple links that have the same connection address
(e.g., multiple point-to-point links between a pair of routers). In
this situation, the Hellos a BGP peer sends on each such link carry
the same Peering Address. In addition, to eliminate the need of
configuring static routes or enabling IGP for advertising the
loopback addresses, a certain type of routes towards the BGP
neighbor's loopback addresses (i.e. carried in the Local Prefixes
TLV) could be dynamically created once the BGP neighbor has been
discovered. The administrative distance of such type of routes MUST
be smaller than their equivalents which are learnt via the normal BGP
update messages. Otherwise, circular dependency problem would occur
once these loopback addresses are advertised via the normal BGP
update messages as well.
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BGP uses the regular receipt of BGP Hellos to indicate a peer's
intent to keep BGP session identified by the Hello. A BGP peer
maintains a hold timer with each Hello adjacency that it restarts
when it receives a Hello that matches the adjacency. If the timer
expires without receipt of a matching Hello from the peer, BGP
concludes that the peer no longer wishes to keep BGP session for that
link or that the peer has failed. The BGP peer then deletes the
Hello adjacency. The route towards the BGP neighbor's loopback
address that had been dynamically created due to that BGP Hello
adjacency SHOULD be deleted accordingly. When the last Hello
adjacency for an BGP session is deleted, the BGP peer terminates the
BGP session and closing the transport connection.
5. Contributors
Satya Mohanty
Cisco
Email: satyamoh@cisco.com
Shunwan Zhuang
Huawei
Email: zhuangshunwan@huawei.com
Chao Huang
Alibaba Inc
Email: jingtan.hc@alibaba-inc.com
Guixin Bao
Alibaba Inc
Email: guixin.bgx@alibaba-inc.com
Jinghui Liu
Ruijie Networks
Email: liujh@ruijie.com.cn
Zhichun Jiang
Tecent
Email: zcjiang@tencent.com
6. Acknowledgements
The authors would like to thank Enke Chen for his valuable comments
and suggestions on this document.
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7. IANA Considerations
7.1. BGP Hello Message
This document requests IANA to allocate a new UDP port (179 is the
preferred number ) and a BGP message type code for BGP Hello message.
Value TLV Name Reference
----- ------------------------------------ -------------
Service Name: BGP-HELLO
Transport Protocol(s): UDP
Assignee: IESG <iesg@ietf.org>
Contact: IETF Chair <chair@ietf.org>.
Description: BGP Hello Message.
Reference: This document -- draft-xu-idr-neighbor-autodiscovery.
Port Number: TBD1 (179 is the preferred value) -- To be assigned by IANA.
7.2. TLVs of BGP Hello Message
This document requests IANA to create a new registry "TLVs of BGP
Hello Message" with the following registration procedure:
Registry Name: TLVs of BGP Hello Message.
Value TLV Name Reference
------- ------------------------------------------ -------------
0 Reserved This document
1 Accepted ASN List This document
2 Peering Address This document
3 Local Prefixes This document
4 Link Attributes This document
5 Neighbor This document
6-65500 Unassigned
65501-65534 Experimental This document
65535 Reserved This document
8. Security Considerations
For security purposes, BGP speakers usually only accept TCP
connection attempts to port 179 from the specified BGP peers or those
within the configured address range. With the BGP neighbor auto-
discovery mechanism, it's configurable to enable or disable sending/
receiving BGP hello messages on the per-interface basis and BGP hello
messages are only exchanged between physically connected peers that
are trustworthy. Therefore, the BGP neighbor auto-discovery
mechanism doesn't introduce additional security risks associated with
BGP.
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In addition, for the BGP sessions with the automatically discovered
peers via the BGP hello messages, the TTL of the TCP/BGP messages
(dest port=179) MUST be set to 255. Any received TCP/BGP message
with TTL being less than 254 MUST be dropped according to [RFC5082].
9. References
9.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC4271] Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A
Border Gateway Protocol 4 (BGP-4)", RFC 4271,
DOI 10.17487/RFC4271, January 2006,
<https://www.rfc-editor.org/info/rfc4271>.
[RFC5036] Andersson, L., Ed., Minei, I., Ed., and B. Thomas, Ed.,
"LDP Specification", RFC 5036, DOI 10.17487/RFC5036,
October 2007, <https://www.rfc-editor.org/info/rfc5036>.
[RFC5082] Gill, V., Heasley, J., Meyer, D., Savola, P., Ed., and C.
Pignataro, "The Generalized TTL Security Mechanism
(GTSM)", RFC 5082, DOI 10.17487/RFC5082, October 2007,
<https://www.rfc-editor.org/info/rfc5082>.
[RFC8279] Wijnands, IJ., Ed., Rosen, E., Ed., Dolganow, A.,
Przygienda, T., and S. Aldrin, "Multicast Using Bit Index
Explicit Replication (BIER)", RFC 8279,
DOI 10.17487/RFC8279, November 2017,
<https://www.rfc-editor.org/info/rfc8279>.
9.2. Informative References
[I-D.keyupate-lsvr-bgp-spf]
Patel, K., Lindem, A., Zandi, S., and W. Henderickx,
"Shortest Path Routing Extensions for BGP Protocol",
draft-keyupate-lsvr-bgp-spf-00 (work in progress), March
2018.
[RFC7938] Lapukhov, P., Premji, A., and J. Mitchell, Ed., "Use of
BGP for Routing in Large-Scale Data Centers", RFC 7938,
DOI 10.17487/RFC7938, August 2016,
<https://www.rfc-editor.org/info/rfc7938>.
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Authors' Addresses
Xiaohu Xu
Alibaba Inc
Email: xiaohu.xxh@alibaba-inc.com
Kunyang Bi
Huawei
Email: bikunyang@huawei.com
Jeff Tantsura
Nuage Networks
Email: jefftant.ietf@gmail.com
Nikos Triantafillis
LinkedIn
Email: nikos@linkedin.com
Ketan Talaulikar
Cisco
Email: ketant@cisco.com
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