draft-ietf-idr-bgp-optimal-route-reflection-13.txt | draft-ietf-idr-bgp-optimal-route-reflection-14.txt | |||
---|---|---|---|---|
IDR Working Group R. Raszuk, Ed. | IDR Working Group R. Raszuk, Ed. | |||
Internet-Draft Bloomberg LP | Internet-Draft Bloomberg LP | |||
Intended status: Standards Track C. Cassar | Intended status: Standards Track C. Cassar | |||
Expires: July 9, 2017 Cisco Systems | Expires: February 12, 2018 Cisco Systems | |||
E. Aman | E. Aman | |||
Telia Company | Telia Company | |||
B. Decraene | B. Decraene | |||
S. Litkowski | ||||
Orange | Orange | |||
K. Wang | K. Wang | |||
Juniper Networks | Juniper Networks | |||
January 5, 2017 | August 11, 2017 | |||
BGP Optimal Route Reflection (BGP-ORR) | BGP Optimal Route Reflection (BGP-ORR) | |||
draft-ietf-idr-bgp-optimal-route-reflection-13 | draft-ietf-idr-bgp-optimal-route-reflection-14 | |||
Abstract | Abstract | |||
This document proposes a solution for BGP route reflectors to allow | This document proposes a solution for BGP route reflectors to allow | |||
them to choose the best path their clients would have chosen under | them to choose the best path their clients would have chosen under | |||
the same conditions, without requiring further state or any new | the same conditions, without requiring further state or any new | |||
features to be placed on the clients. This facilitates, for example, | features to be placed on the clients. This facilitates, for example, | |||
best exit point policy (hot potato routing). This solution is | best exit point policy (hot potato routing). This solution is | |||
primarily applicable in deployments using centralized route | primarily applicable in deployments using centralized route | |||
reflectors. | reflectors. | |||
skipping to change at page 2, line 6 ¶ | skipping to change at page 2, line 4 ¶ | |||
Internet-Drafts are working documents of the Internet Engineering | Internet-Drafts are working documents of the Internet Engineering | |||
Task Force (IETF). Note that other groups may also distribute | Task Force (IETF). Note that other groups may also distribute | |||
working documents as Internet-Drafts. The list of current Internet- | working documents as Internet-Drafts. The list of current Internet- | |||
Drafts is at http://datatracker.ietf.org/drafts/current/. | Drafts is at http://datatracker.ietf.org/drafts/current/. | |||
Internet-Drafts are draft documents valid for a maximum of six months | Internet-Drafts are draft documents valid for a maximum of six months | |||
and may be updated, replaced, or obsoleted by other documents at any | and may be updated, replaced, or obsoleted by other documents at any | |||
time. It is inappropriate to use Internet-Drafts as reference | time. It is inappropriate to use Internet-Drafts as reference | |||
material or to cite them other than as "work in progress." | material or to cite them other than as "work in progress." | |||
This Internet-Draft will expire on February 12, 2018. | ||||
This Internet-Draft will expire on July 9, 2017. | ||||
Copyright Notice | Copyright Notice | |||
Copyright (c) 2017 IETF Trust and the persons identified as the | Copyright (c) 2017 IETF Trust and the persons identified as the | |||
document authors. All rights reserved. | document authors. All rights reserved. | |||
This document is subject to BCP 78 and the IETF Trust's Legal | This document is subject to BCP 78 and the IETF Trust's Legal | |||
Provisions Relating to IETF Documents | Provisions Relating to IETF Documents | |||
(http://trustee.ietf.org/license-info) in effect on the date of | (http://trustee.ietf.org/license-info) in effect on the date of | |||
publication of this document. Please review these documents | publication of this document. Please review these documents | |||
carefully, as they describe your rights and restrictions with respect | carefully, as they describe your rights and restrictions with respect | |||
to this document. Code Components extracted from this document must | to this document. Code Components extracted from this document must | |||
include Simplified BSD License text as described in Section 4.e of | include Simplified BSD License text as described in Section 4.e of | |||
the Trust Legal Provisions and are provided without warranty as | the Trust Legal Provisions and are provided without warranty as | |||
described in the Simplified BSD License. | described in the Simplified BSD License. | |||
Table of Contents | Table of Contents | |||
1. Definitions of Terms Used in This Memo . . . . . . . . . . . 2 | 1. Definitions of Terms Used in This Memo . . . . . . . . . . . 2 | |||
2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 | 2. Authors . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 | |||
2.1. Problem Statement . . . . . . . . . . . . . . . . . . . . 3 | 3. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 | |||
2.2. Existing/Alternative Solutions . . . . . . . . . . . . . 4 | 3.1. Problem Statement . . . . . . . . . . . . . . . . . . . . 4 | |||
3. Proposed Solutions . . . . . . . . . . . . . . . . . . . . . 5 | 3.2. Existing/Alternative Solutions . . . . . . . . . . . . . 5 | |||
3.1. Client's Perspective IGP Based Best Path Selection . . . 6 | 4. Proposed Solutions . . . . . . . . . . . . . . . . . . . . . 6 | |||
3.2. Client's Perspective Policy Based Best Path Selection . . 6 | 4.1. Client's Perspective IGP Based Best Path Selection . . . 6 | |||
3.3. Solution Interactions . . . . . . . . . . . . . . . . . . 7 | 4.2. Client's Perspective Policy Based Best Path Selection . . 7 | |||
4. CPU and Memory Scalability . . . . . . . . . . . . . . . . . 8 | 4.3. Solution Interactions . . . . . . . . . . . . . . . . . . 8 | |||
5. Advantages and Deployment Considerations . . . . . . . . . . 9 | 5. CPU and Memory Scalability . . . . . . . . . . . . . . . . . 9 | |||
6. Security Considerations . . . . . . . . . . . . . . . . . . . 9 | 6. Advantages and Deployment Considerations . . . . . . . . . . 9 | |||
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10 | 7. Security Considerations . . . . . . . . . . . . . . . . . . . 10 | |||
8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 10 | 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10 | |||
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 10 | 9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 10 | |||
9.1. Normative References . . . . . . . . . . . . . . . . . . 10 | 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 11 | |||
9.2. Informative References . . . . . . . . . . . . . . . . . 10 | 10.1. Normative References . . . . . . . . . . . . . . . . . . 11 | |||
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 11 | 10.2. Informative References . . . . . . . . . . . . . . . . . 11 | |||
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 12 | ||||
1. Definitions of Terms Used in This Memo | 1. Definitions of Terms Used in This Memo | |||
NLRI - Network Layer Reachability Information. | NLRI - Network Layer Reachability Information. | |||
RIB - Routing Information Base. | RIB - Routing Information Base. | |||
AS - Autonomous System number. | AS - Autonomous System number. | |||
VRF - Virtual Routing and Forwarding instance. | VRF - Virtual Routing and Forwarding instance. | |||
skipping to change at page 3, line 21 ¶ | skipping to change at page 3, line 19 ¶ | |||
L3VPN - Layer 3 Virtual Private Networks RFC4364 | L3VPN - Layer 3 Virtual Private Networks RFC4364 | |||
6PE - IPv6 Provider Edge Router | 6PE - IPv6 Provider Edge Router | |||
IGP - Interior Gateway Protocol | IGP - Interior Gateway Protocol | |||
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", | The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", | |||
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this | "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this | |||
document are to be interpreted as described in [RFC2119] | document are to be interpreted as described in [RFC2119] | |||
2. Introduction | 2. Authors | |||
Following authors substantially contributed to the current format of | ||||
the document: | ||||
Stephane Litkowski | ||||
Orange | ||||
9 rue du chene germain | ||||
Cesson Sevigne, 35512 | ||||
France | ||||
stephane.litkowski@orange.com | ||||
Adam Chappell | ||||
Interoute Communications | ||||
31st Floor | ||||
25 Canada Square | ||||
London, E14 5LQ | ||||
United Kingdom | ||||
adam.chappell@interoute.com | ||||
3. Introduction | ||||
There are three types of BGP deployments within Autonomous Systems | There are three types of BGP deployments within Autonomous Systems | |||
today: full mesh, confederations and route reflection. BGP route | today: full mesh, confederations and route reflection. BGP route | |||
reflection [RFC4456] is the most popular way to distribute BGP routes | reflection [RFC4456] is the most popular way to distribute BGP routes | |||
between BGP speakers belonging to the same Autonomous System. In | between BGP speakers belonging to the same Autonomous System. In | |||
some situations, this method suffers from non-optimal path selection. | some situations, this method suffers from non-optimal path selection. | |||
2.1. Problem Statement | 3.1. Problem Statement | |||
[RFC4456] asserts that, because the Interior Gateway Protocol (IGP) | [RFC4456] asserts that, because the Interior Gateway Protocol (IGP) | |||
cost to a given point in the network will vary across routers, "the | cost to a given point in the network will vary across routers, "the | |||
route reflection approach may not yield the same route selection | route reflection approach may not yield the same route selection | |||
result as that of the full IBGP mesh approach." One practical | result as that of the full IBGP mesh approach." One practical | |||
implication of this assertion is that the deployment of route | implication of this assertion is that the deployment of route | |||
reflection may thwart the ability to achieve hot potato routing. Hot | reflection may thwart the ability to achieve hot potato routing. Hot | |||
potato routing attempts to direct traffic to the best AS exit point | potato routing attempts to direct traffic to the best AS exit point | |||
in cases where no higher priority policy dictates otherwise. As a | in cases where no higher priority policy dictates otherwise. As a | |||
consequence of the route reflection method, the choice of exit point | consequence of the route reflection method, the choice of exit point | |||
skipping to change at page 4, line 29 ¶ | skipping to change at page 5, line 4 ¶ | |||
paths for a given prefix will typically pick its best path and only | paths for a given prefix will typically pick its best path and only | |||
advertise that best path to its clients. If the best path for a | advertise that best path to its clients. If the best path for a | |||
prefix is selected on the basis of an IGP tie break, the path | prefix is selected on the basis of an IGP tie break, the path | |||
advertised will be the exit point closest to the route reflector. | advertised will be the exit point closest to the route reflector. | |||
But the clients will be in a different place in the network topology | But the clients will be in a different place in the network topology | |||
than the route reflector. In networks where the route reflectors are | than the route reflector. In networks where the route reflectors are | |||
not in the forwarding path, this difference will be even more acute. | not in the forwarding path, this difference will be even more acute. | |||
Beside this, there are also deployment scenarios where service | Beside this, there are also deployment scenarios where service | |||
providers want to have more control of choosing the exit points for | providers want to have more control of choosing the exit points for | |||
clients based on other factors like traffic type, traffic load, etc. | clients based on other factors like traffic type, traffic load, etc. | |||
This further complicated the issue and makes it less likely for the | This further complicated the issue and makes it less likely for the | |||
route reflector to select the best path from the client's | route reflector to select the best path from the client's | |||
perspective. It follows that the best path chosen by the route | perspective. It follows that the best path chosen by the route | |||
reflector is not necessarily the same as the path which would have | reflector is not necessarily the same as the path which would have | |||
been chosen by the client if the client had considered the same set | been chosen by the client if the client had considered the same set | |||
of candidate paths as the route reflector. | of candidate paths as the route reflector. | |||
2.2. Existing/Alternative Solutions | 3.2. Existing/Alternative Solutions | |||
One possible valid solution or workaround to the best path selection | One possible valid solution or workaround to the best path selection | |||
problem requires sending all domain external paths from the RR to all | problem requires sending all domain external paths from the RR to all | |||
its clients. This approach suffers the significant drawback of | its clients. This approach suffers the significant drawback of | |||
pushing a large amount of BGP state to all edge routers. Many | pushing a large amount of BGP state to all edge routers. Many | |||
networks receive full Internet routing information in a large number | networks receive full Internet routing information in a large number | |||
of locations. This could easily result in tens of paths for each | of locations. This could easily result in tens of paths for each | |||
prefix that would need to be distributed to clients. | prefix that would need to be distributed to clients. | |||
Notwithstanding this drawback, there are a number of reasons for | Notwithstanding this drawback, there are a number of reasons for | |||
skipping to change at page 5, line 16 ¶ | skipping to change at page 5, line 39 ¶ | |||
result in the distribution of 2, 3 or n (where n is a small number) | result in the distribution of 2, 3 or n (where n is a small number) | |||
good paths rather than all domain external paths. While the route | good paths rather than all domain external paths. While the route | |||
reflector chooses one set of n paths and distributes those same n | reflector chooses one set of n paths and distributes those same n | |||
paths to all its route reflector clients, those n paths may not be | paths to all its route reflector clients, those n paths may not be | |||
the right n paths for all clients. In the context of the problem | the right n paths for all clients. In the context of the problem | |||
described above, those n paths will not necessarily include the best | described above, those n paths will not necessarily include the best | |||
exit point out of the network for each route reflector client. The | exit point out of the network for each route reflector client. The | |||
mechanisms proposed in this document are likely to be complementary | mechanisms proposed in this document are likely to be complementary | |||
to mechanisms aimed at improving path diversity. | to mechanisms aimed at improving path diversity. | |||
Another possibility to optimize exit points would be installing | Another possibility to optimize exit point selection is the | |||
physical hardware at various IGP locations or what is quite unlikely | implementation of distributed reflector functionality at key IGP | |||
to attach Route Reflectors over manually created tunnels. | locations in order to ensure that these locations see their | |||
viewpoints respected in exit selection. Typically, however, this | ||||
requires the installation of physical nodes to implement the | ||||
reflection, and if exit policy subsequently changes, the reflector | ||||
placement and position can become inappropriate. | ||||
The paradigm of control plane is shifting from traditional routers to | To counter the burden of physical installation, it's possible to | |||
x86 virtual space or even cloud. As result without this proposal | build a logical overlay of tunnels with appropriate IGP metrics in | |||
operators have choice of their route reflectors distributing | order to simulate closeness to key locations required to implement | |||
suboptimal paths or distributing all paths and in turn allowing | exit policy. There is significant complexity overhead in this | |||
clients to make independent best path selection. | approach, however, to make it typically undesirable. | |||
Now while the latter could be even an option in router's world more | Trends in control plane decoupling are causing a shift from | |||
and more BGP is being observed on the compute servers where sending | traditional routers to compute virtualisation platforms, or even | |||
there all present in an AS BGP paths would be for one undesired as | third-party cloud platforms. As a result, without this proposal, | |||
well would require to run also IGP there. Let's also note that | operators are left with a difficult choice for the distribution and | |||
number of paths per BGP prefix varies a lot. Depending on the | reflection of address families with significant exit diversity: | |||
network it can be anywhere from few to few hundreds. | ||||
3. Proposed Solutions | o centralised path selection, and tolerate the associated suboptimal | |||
paths, | ||||
o defer selection to end clients, but lose potential route scale | ||||
capacity | ||||
The latter can be a viable option, but it is clearly a decision that | ||||
needs to be made on an application and address family basis, with | ||||
strong consideration for the number of available paths per prefix | ||||
(which may even vary per prefix range, depending on peering policy, | ||||
e.g. consider bilateral peerings versus onward transit arrangements) | ||||
4. Proposed Solutions | ||||
The goal of this document is to allow a route reflector to choose the | The goal of this document is to allow a route reflector to choose the | |||
best path the client would have chosen had the client considered the | best path the client would have chosen had the client considered the | |||
same set of candidate paths the reflector has available. For | same set of candidate paths the reflector has available. For | |||
purposes of route selection, the perspective of a client can differ | purposes of route selection, the perspective of a client can differ | |||
from that of a route reflector or another client in two distinct | from that of a route reflector or another client in two distinct | |||
ways: it can, and usually will, have a different position in the IGP | ways: it can, and usually will, have a different position in the IGP | |||
topology, and it can have a different routing policy. These | topology, and it can have a different routing policy. These | |||
correspond to the issues described earlier. Accordingly, we propose | correspond to the issues described earlier. Accordingly, we propose | |||
two distinct modifications to the best path algorithm, to address | two distinct modifications to the best path algorithm, to address | |||
skipping to change at page 6, line 8 ¶ | skipping to change at page 6, line 47 ¶ | |||
considered the same set of candidate paths. | considered the same set of candidate paths. | |||
Both modifications rely upon all route reflectors learning all paths | Both modifications rely upon all route reflectors learning all paths | |||
which are eligible for consideration. In order to satisfy this | which are eligible for consideration. In order to satisfy this | |||
requirement, path diversity enhancing mechanisms such as ADD-PATH/ | requirement, path diversity enhancing mechanisms such as ADD-PATH/ | |||
diverse paths may need to be deployed between route reflectors. | diverse paths may need to be deployed between route reflectors. | |||
A significant advantage of these approaches is that the RR clients do | A significant advantage of these approaches is that the RR clients do | |||
not need to run new software or hardware. | not need to run new software or hardware. | |||
3.1. Client's Perspective IGP Based Best Path Selection | 4.1. Client's Perspective IGP Based Best Path Selection | |||
The core of this solution is the ability for an operator to specify | The core of this solution is the ability for an operator to specify | |||
on a per route reflector basis or per peer/update group basis or per | on a per route reflector basis or per peer/update group basis or per | |||
peer basis the virtual IGP location placement of the route reflector. | peer basis the virtual IGP location placement of the route reflector. | |||
This enables having a given group of clients receive routes with | This enables having a given group of clients receive routes with | |||
optimal distance to the next hops from the position of the configured | optimal distance to the next hops from the position of the configured | |||
virtual IGP location. This also provides for freedom of route | virtual IGP location. This also provides for freedom of route | |||
reflector location and allows transient or permanent migration of | reflector location and allows transient or permanent migration of | |||
such network control plane function to optimal location. | such network control plane function to optimal location. | |||
skipping to change at page 6, line 41 ¶ | skipping to change at page 7, line 31 ¶ | |||
operator may configure it manually, implementation may automate it | operator may configure it manually, implementation may automate it | |||
based on specified heuristic or it can be computed centrally and | based on specified heuristic or it can be computed centrally and | |||
configured by an external system. | configured by an external system. | |||
The solution does not require any BGP or IGP protocol changes as | The solution does not require any BGP or IGP protocol changes as | |||
required changes are contained within the RR implementation. | required changes are contained within the RR implementation. | |||
The solution applies to NLRIs of all address families which can be | The solution applies to NLRIs of all address families which can be | |||
route reflected. | route reflected. | |||
3.2. Client's Perspective Policy Based Best Path Selection | 4.2. Client's Perspective Policy Based Best Path Selection | |||
Optimal route reflection based on virtual IGP location could reflect | Optimal route reflection based on virtual IGP location could reflect | |||
the best path to the client from IGP cost perspective. However, | the best path to the client from IGP cost perspective. However, | |||
there are also cases where the client might want best path from | there are also cases where the client might want best path from | |||
perspectives beyond IGP cost. Examples include, but not limited to: | perspectives beyond IGP cost. Examples include, but not limited to: | |||
o Select the best path for the clients from a traffic engineering | o Select the best path for the clients from a traffic engineering | |||
perspective. | perspective. | |||
o Dedicate certain exit points for certain ingress points. | o Dedicate certain exit points for certain ingress points. | |||
skipping to change at page 7, line 21 ¶ | skipping to change at page 8, line 12 ¶ | |||
be applied to the candidate paths to select the final paths to | be applied to the candidate paths to select the final paths to | |||
advertise to the clients. | advertise to the clients. | |||
The policy is applied on the route reflector on behalf of its | The policy is applied on the route reflector on behalf of its | |||
clients. This way, the route reflector will be able to reflect only | clients. This way, the route reflector will be able to reflect only | |||
the optimal paths to the clients. An additional advantage of this | the optimal paths to the clients. An additional advantage of this | |||
approach is that configuration need only be done on a small number of | approach is that configuration need only be done on a small number of | |||
route reflectors rather than a significantly larger number of | route reflectors rather than a significantly larger number of | |||
clients. | clients. | |||
3.3. Solution Interactions | 4.3. Solution Interactions | |||
Depending on the actual deployment scenarios, service providers may | Depending on the actual deployment scenarios, service providers may | |||
configure IGP based optimal route reflection or policy based optimal | configure IGP based optimal route reflection or policy based optimal | |||
route reflection. It's also possible to configure both approaches | route reflection. It's also possible to configure both approaches | |||
together. In that case, policy based optimal route reflection will | together. In that case, policy based optimal route reflection will | |||
be applied first to select the candidate paths. Subsequently, IGP | be applied first to select the candidate paths. Subsequently, IGP | |||
based optimal route reflection will be applied on top of the | based optimal route reflection will be applied on top of the | |||
candidate paths to select the final path to advertise to the client. | candidate paths to select the final path to advertise to the client. | |||
The expected use case for optimal route reflection is to avoid | The expected use case for optimal route reflection is to avoid | |||
skipping to change at page 8, line 15 ¶ | skipping to change at page 9, line 7 ¶ | |||
similar IGP location can be grouped into the same peer group. A | similar IGP location can be grouped into the same peer group. A | |||
virtual IGP location is then specified for the peer group. The | virtual IGP location is then specified for the peer group. The | |||
virtual location is usually specified as the location of one of the | virtual location is usually specified as the location of one of the | |||
clients from the peer group or an ABR to the area where clients are | clients from the peer group or an ABR to the area where clients are | |||
located. Also, one or more backup virtual location SHOULD be allowed | located. Also, one or more backup virtual location SHOULD be allowed | |||
to be specified for redundancy. Implementations may wish to take | to be specified for redundancy. Implementations may wish to take | |||
advantage of peer group mechanisms in order to provide for better | advantage of peer group mechanisms in order to provide for better | |||
scalability of optimal route reflector client groups with similar | scalability of optimal route reflector client groups with similar | |||
properties. | properties. | |||
4. CPU and Memory Scalability | 5. CPU and Memory Scalability | |||
For IGP based optimal route reflection, determining the shortest path | For IGP based optimal route reflection, determining the shortest path | |||
and associated cost between any two arbitrary points in a network | and associated cost between any two arbitrary points in a network | |||
based on the IGP topology learned by a router is expected to add some | based on the IGP topology learned by a router is expected to add some | |||
extra cost in terms of CPU resources. However SPF tree generation | extra cost in terms of CPU resources. However SPF tree generation | |||
code is now implemented efficiently in a number of implementations, | code is now implemented efficiently in a number of implementations, | |||
and therefore this is not expected to be a major drawback. The | and therefore this is not expected to be a major drawback. The | |||
number of SPTs computed is expected to be of the order of the number | number of SPTs computed is expected to be of the order of the number | |||
of clients of an RR whenever a topology change is detected. Advanced | of clients of an RR whenever a topology change is detected. Advanced | |||
optimizations like partial and incremental SPF may also be exploited. | optimizations like partial and incremental SPF may also be exploited. | |||
skipping to change at page 9, line 5 ¶ | skipping to change at page 9, line 41 ¶ | |||
today, this avenue to scaling up the route reflection infrastructure | today, this avenue to scaling up the route reflection infrastructure | |||
would be available. | would be available. | |||
If we consider the overall network wide cost/benefit factor, the only | If we consider the overall network wide cost/benefit factor, the only | |||
alternative to achieve the same level of optimality would require | alternative to achieve the same level of optimality would require | |||
significantly increasing state on the edges of the network. This | significantly increasing state on the edges of the network. This | |||
will consume CPU and memory resources on all BGP speakers in the | will consume CPU and memory resources on all BGP speakers in the | |||
network. Building this client perspective into the route reflectors | network. Building this client perspective into the route reflectors | |||
seems appropriate. | seems appropriate. | |||
5. Advantages and Deployment Considerations | 6. Advantages and Deployment Considerations | |||
The solutions described provide a model for integrating the client | The solutions described provide a model for integrating the client | |||
perspective into the best path computation for RRs. More | perspective into the best path computation for RRs. More | |||
specifically, the choice of BGP path factors in either the IGP cost | specifically, the choice of BGP path factors in either the IGP cost | |||
between the client and the nexthop (rather than the distance from the | between the client and the nexthop (rather than the distance from the | |||
RR to the nexthop) or user configured policies. | RR to the nexthop) or other user configured policies. | |||
Implementation to be declared as compliant with this memo should | Implementations considered compliant with this memo allow the | |||
allow to configure per instance or per group of peers logical | configuration of a logical location from which the best path will be | |||
location from which either for the entire instance or for set of | computed, on the basis of either a peer, a peer group, or an entire | |||
peers best path will be computed. | routing instance. | |||
These solutions can be deployed in traditional hop-by-hop forwarding | These solutions can be deployed in traditional hop-by-hop forwarding | |||
networks as well as in end-to-end tunneled environments. In the | networks as well as in end-to-end tunneled environments. In the | |||
networks where there are multiple route reflectors and hop-by-hop | networks where there are multiple route reflectors and hop-by-hop | |||
forwarding without encapsulation, such optimizations should be | forwarding without encapsulation, such optimizations should be | |||
enabled in a consistent way on all route reflectors. Otherwise | enabled in a consistent way on all route reflectors. Otherwise | |||
clients may receive an inconsistent view of the network and in turn | clients may receive an inconsistent view of the network and in turn | |||
lead to intra-domain forwarding loops. | lead to intra-domain forwarding loops. | |||
With this approach, an ISP can effect a hot potato routing policy | With this approach, an ISP can effect a hot potato routing policy | |||
skipping to change at page 9, line 48 ¶ | skipping to change at page 10, line 37 ¶ | |||
The proposals allow for a fast and safe transition to a BGP control | The proposals allow for a fast and safe transition to a BGP control | |||
plane with centralized route reflection without compromising an | plane with centralized route reflection without compromising an | |||
operator's closest exit operational principle. This enables edge-to- | operator's closest exit operational principle. This enables edge-to- | |||
edge LSP/IP encapsulation for traffic to IPv4 and IPv6 prefixes. | edge LSP/IP encapsulation for traffic to IPv4 and IPv6 prefixes. | |||
Regarding the client's IGP best-path selection, it should be self | Regarding the client's IGP best-path selection, it should be self | |||
evident that this solution does not interfere with policies enforced | evident that this solution does not interfere with policies enforced | |||
above IGP tie breaking in the BGP best path algorithm. | above IGP tie breaking in the BGP best path algorithm. | |||
6. Security Considerations | 7. Security Considerations | |||
No new security issues are introduced to the BGP protocol by this | No new security issues are introduced to the BGP protocol by this | |||
specification. | specification. | |||
7. IANA Considerations | 8. IANA Considerations | |||
This document does not request any IANA allocations. | This document does not request any IANA allocations. | |||
8. Acknowledgments | 9. Acknowledgments | |||
Authors would like to thank Keyur Patel, Eric Rosen, Clarence | Authors would like to thank Keyur Patel, Eric Rosen, Clarence | |||
Filsfils, Uli Bornhauser, Russ White, Jakob Heitz, Mike Shand, Jon | Filsfils, Uli Bornhauser, Russ White, Jakob Heitz, Mike Shand, Jon | |||
Mitchell, John Scudder, Jeff Haas, Martin Djernaes and Daniele | Mitchell, John Scudder, Jeff Haas, Martin Djernaes and Daniele | |||
Ceccarelli for their valuable input. | Ceccarelli for their valuable input. | |||
9. References | 10. References | |||
9.1. Normative References | 10.1. Normative References | |||
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate | [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate | |||
Requirement Levels", BCP 14, RFC 2119, | Requirement Levels", BCP 14, RFC 2119, | |||
DOI 10.17487/RFC2119, March 1997, | DOI 10.17487/RFC2119, March 1997, | |||
<http://www.rfc-editor.org/info/rfc2119>. | <http://www.rfc-editor.org/info/rfc2119>. | |||
[RFC4271] Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A | [RFC4271] Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A | |||
Border Gateway Protocol 4 (BGP-4)", RFC 4271, | Border Gateway Protocol 4 (BGP-4)", RFC 4271, | |||
DOI 10.17487/RFC4271, January 2006, | DOI 10.17487/RFC4271, January 2006, | |||
<http://www.rfc-editor.org/info/rfc4271>. | <http://www.rfc-editor.org/info/rfc4271>. | |||
[RFC4360] Sangli, S., Tappan, D., and Y. Rekhter, "BGP Extended | [RFC4360] Sangli, S., Tappan, D., and Y. Rekhter, "BGP Extended | |||
Communities Attribute", RFC 4360, DOI 10.17487/RFC4360, | Communities Attribute", RFC 4360, DOI 10.17487/RFC4360, | |||
February 2006, <http://www.rfc-editor.org/info/rfc4360>. | February 2006, <http://www.rfc-editor.org/info/rfc4360>. | |||
[RFC5492] Scudder, J. and R. Chandra, "Capabilities Advertisement | [RFC5492] Scudder, J. and R. Chandra, "Capabilities Advertisement | |||
with BGP-4", RFC 5492, DOI 10.17487/RFC5492, February | with BGP-4", RFC 5492, DOI 10.17487/RFC5492, February | |||
2009, <http://www.rfc-editor.org/info/rfc5492>. | 2009, <http://www.rfc-editor.org/info/rfc5492>. | |||
9.2. Informative References | 10.2. Informative References | |||
[I-D.ietf-idr-add-paths] | [I-D.ietf-idr-add-paths] | |||
Walton, D., Retana, A., Chen, E., and J. Scudder, | Walton, D., Retana, A., Chen, E., and J. Scudder, | |||
"Advertisement of Multiple Paths in BGP", draft-ietf-idr- | "Advertisement of Multiple Paths in BGP", draft-ietf-idr- | |||
add-paths-15 (work in progress), May 2016. | add-paths-15 (work in progress), May 2016. | |||
[RFC1997] Chandra, R., Traina, P., and T. Li, "BGP Communities | [RFC1997] Chandra, R., Traina, P., and T. Li, "BGP Communities | |||
Attribute", RFC 1997, DOI 10.17487/RFC1997, August 1996, | Attribute", RFC 1997, DOI 10.17487/RFC1997, August 1996, | |||
<http://www.rfc-editor.org/info/rfc1997>. | <http://www.rfc-editor.org/info/rfc1997>. | |||
skipping to change at page 12, line 27 ¶ | skipping to change at page 13, line 19 ¶ | |||
Email: erik.aman@teliacompany.com | Email: erik.aman@teliacompany.com | |||
Bruno Decraene | Bruno Decraene | |||
Orange | Orange | |||
38-40 rue du General Leclerc | 38-40 rue du General Leclerc | |||
Issy les Moulineaux cedex 9 92794 | Issy les Moulineaux cedex 9 92794 | |||
France | France | |||
Email: bruno.decraene@orange.com | Email: bruno.decraene@orange.com | |||
Stephane Litkowski | ||||
Orange | ||||
9 rue du chene germain | ||||
Cesson Sevigne 35512 | ||||
France | ||||
Email: stephane.litkowski@orange.com | ||||
Kevin Wang | Kevin Wang | |||
Juniper Networks | Juniper Networks | |||
10 Technology Park Drive | 10 Technology Park Drive | |||
Westford, MA 01886 | Westford, MA 01886 | |||
USA | USA | |||
Email: kfwang@juniper.net | Email: kfwang@juniper.net | |||
End of changes. 28 change blocks. | ||||
64 lines changed or deleted | 93 lines changed or added | |||
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