Network Working Group X. Xu
Internet-Draft Huawei
Intended status: Informational R. Raszuk
Expires: May 13, 2016 Mirantis Inc.
C. Jacquenet
Orange
T. Boyes
Bloomberg LP
B. Fee
Extreme Networks
November 10, 2015
Virtual Subnet: A BGP/MPLS IP VPN-based Subnet Extension Solution
draft-ietf-bess-virtual-subnet-04
Abstract
This document describes a BGP/MPLS IP VPN-based subnet extension
solution referred to as Virtual Subnet, which can be used for
building Layer 3 network virtualization overlays within and/or
between data centers.
Status of This Memo
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This Internet-Draft will expire on May 13, 2016.
Copyright Notice
Copyright (c) 2015 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
(http://trustee.ietf.org/license-info) in effect on the date of
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Solution Description . . . . . . . . . . . . . . . . . . . . 4
3.1. Unicast . . . . . . . . . . . . . . . . . . . . . . . . . 4
3.1.1. Intra-subnet Unicast . . . . . . . . . . . . . . . . 4
3.1.2. Inter-subnet Unicast . . . . . . . . . . . . . . . . 5
3.2. Multicast . . . . . . . . . . . . . . . . . . . . . . . . 8
3.3. Host Discovery . . . . . . . . . . . . . . . . . . . . . 9
3.4. ARP/ND Proxy . . . . . . . . . . . . . . . . . . . . . . 9
3.5. Host Mobility . . . . . . . . . . . . . . . . . . . . . . 9
3.6. Forwarding Table Scalability on Data Center Switches . . 10
3.7. ARP/ND Cache Table Scalability on Default Gateways . . . 10
3.8. ARP/ND and Unknown Uncast Flood Avoidance . . . . . . . . 10
3.9. Path Optimization . . . . . . . . . . . . . . . . . . . . 10
4. Limitations . . . . . . . . . . . . . . . . . . . . . . . . . 11
4.1. Non-support of Non-IP Traffic . . . . . . . . . . . . . . 11
4.2. Non-support of IP Broadcast and Link-local Multicast . . 11
4.3. TTL and Traceroute . . . . . . . . . . . . . . . . . . . 11
5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 12
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12
7. Security Considerations . . . . . . . . . . . . . . . . . . . 12
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 12
8.1. Normative References . . . . . . . . . . . . . . . . . . 12
8.2. Informative References . . . . . . . . . . . . . . . . . 13
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 13
1. Introduction
For business continuity purpose, Virtual Machine (VM) migration
across data centers is commonly used in situations such as data
center maintenance, data center migration, data center consolidation,
data center expansion, and data center disaster avoidance. It's
generally admitted that IP renumbering of servers (i.e., VMs) after
the migration is usually complex and costly at the risk of extending
the business downtime during the process of migration. To allow the
migration of a VM from one data center to another without IP
renumbering, the subnet on which the VM resides needs to be extended
across these data centers.
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To achieve subnet extension across multiple Infrastructure-as-
a-Service (IaaS) cloud data centers in a scalable way, the following
requirements and challenges must be considered:
a. VPN Instance Space Scalability: In a modern cloud data center
environment, thousands or even tens of thousands of tenants could
be hosted over a shared network infrastructure. For security and
performance isolation purposes, these tenants need to be isolated
from one another.
b. Forwarding Table Scalability: With the development of server
virtualization technologies, it's not uncommon for a single cloud
data center to contain millions of VMs. This number already
implies a big challenge on the forwarding table scalability of
data center switches. Provided multiple data centers of such
scale were interconnected at Layer 2, this challenge would become
even worse.
c. ARP/ND Cache Table Scalability: [RFC6820] notes that the Address
Resolution Protocol (ARP)/Neighbor Discovery (ND) cache tables
maintained on default gateways within cloud data centers can
raise scalability issues. Therefore, it's very useful if the
ARP/ND cache table size could be prevented from growing by
multiples as the number of data centers to be connected
increases.
d. ARP/ND and Unknown Unicast Flooding: It's well-known that the
flooding of ARP/ND broadcast/multicast and unknown unicast
traffic within large Layer 2 networks would affect the
performance of networks and hosts. As multiple data centers with
each containing millions of VMs are interconnected at Layer 2,
the impact of flooding as mentioned above would become even
worse. As such, it becomes increasingly important to avoid the
flooding of ARP/ND broadcast/multicast and unknown unicast
traffic across data centers.
e. Path Optimization: A subnet usually indicates a location in the
network. However, when a subnet has been extended across
multiple geographically dispersed data center locations, the
location semantics of such subnet is not retained any longer. As
a result, the traffic between a specific user and server, in
different data centers, may first be routed through a third data
center. This suboptimal routing would obviously result in an
unnecessary consumption of the bandwidth resource between data
centers. Furthermore, in the case where traditional VPLS
technology [RFC4761] [RFC4762] is used for data center
interconnect, return traffic from a server may be forwarded to a
default gateway located in a different data center due to the
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configuration in a virtual router redundancy group. This
suboptimal routing would also unnecessarily consume the bandwidth
resource between data centers.
This document describes a BGP/MPLS IP VPN-based subnet extension
solution referred to as Virtual Subnet, which can be used for data
center interconnection while addressing all of the requirements and
challenges as mentioned above. Here the BGP/MPLS IP VPN means both
BGP/MPLS IPv4 VPN [RFC4364] and BGP/MPLS IPv6 VPN [RFC4659]. In
addition, since Virtual Subnet is mainly built on proven technologies
such as BGP/MPLS IP VPN and ARP/ND proxy [RFC0925][RFC1027][RFC4389],
those service providers offering IaaS public cloud services could
rely upon their existing BGP/MPLS IP VPN infrastructures and their
corresponding experiences to realize data center interconnection.
Although Virtual Subnet is described in this document as an approach
for data center interconnection, it actually could be used within
data centers as well.
Note that the approach described in this document is not intended to
achieve an exact emulation of Layer 2 connectivity and therefore it
can only support a restricted Layer 2 connectivity service model with
limitations declared in Section 4. As for the discussion about in
which environment this service model should be suitable, it's outside
the scope of this document.
2. Terminology
This memo makes use of the terms defined in [RFC4364].
3. Solution Description
3.1. Unicast
3.1.1. Intra-subnet Unicast
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+--------------------+
+------------------+ | | +------------------+
|VPN_A:192.0.2.1/24| | | |VPN_A:192.0.2.1/24|
| \ | | | | / |
| +------+ \ ++---+-+ +-+---++/ +------+ |
| |Host A+-----+ PE-1 | | PE-2 +----+Host B| |
| +------+\ ++-+-+-+ +-+-+-++ /+------+ |
| 192.0.2.2/24 | | | | | | 192.0.2.3/24 |
| | | | | | | |
| DC West | | | IP/MPLS Backbone | | | DC East |
+------------------+ | | | | +------------------+
| +--------------------+ |
| |
VRF_A : V VRF_A : V
+------------+---------+--------+ +------------+---------+--------+
| Prefix | Nexthop |Protocol| | Prefix | Nexthop |Protocol|
+------------+---------+--------+ +------------+---------+--------+
|192.0.2.1/32|127.0.0.1| Direct | |192.0.2.1/32|127.0.0.1| Direct |
+------------+---------+--------+ +------------+---------+--------+
|192.0.2.2/32|192.0.2.2| Direct | |192.0.2.2/32| PE-1 | IBGP |
+------------+---------+--------+ +------------+---------+--------+
|192.0.2.3/32| PE-2 | IBGP | |192.0.2.3/32|192.0.2.3| Direct |
+------------+---------+--------+ +------------+---------+--------+
|192.0.2.0/24|192.0.2.1| Direct | |192.0.2.0/24|192.0.2.1| Direct |
+------------+---------+--------+ +------------+---------+--------+
Figure 1: Intra-subnet Unicast Example
As shown in Figure 1, two hosts (i.e., Hosts A and B) belonging to
the same subnet (i.e., 192.0.2.0/24) are located at different data
centers (i.e., DC West and DC East) respectively. PE routers (i.e.,
PE-1 and PE-2) which are used for interconnecting these two data
centers create host routes for their own local hosts respectively and
then advertise them via the BGP/MPLS IP VPN signaling. Meanwhile, an
ARP proxy is enabled on VRF attachment circuits of these PE routers.
Now assume host A sends an ARP request for host B before
communicating with host B. Upon receiving the ARP request, PE-1
acting as an ARP proxy returns its own MAC address as a response.
Host A then sends IP packets for host B to PE-1. PE-1 tunnels such
packets towards PE-2 which in turn forwards them to host B. Thus,
hosts A and B can communicate with each other as if they were located
within the same subnet.
3.1.2. Inter-subnet Unicast
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+--------------------+
+------------------+ | | +------------------+
|VPN_A:192.0.2.1/24| | | |VPN_A:192.0.2.1/24|
| \ | | | | / |
| +------+ \ ++---+-+ +-+---++/ +------+ |
| |Host A+-------+ PE-1 | | PE-2 +-+----+Host B| |
| +------+\ ++-+-+-+ +-+-+-++ | /+------+ |
| 192.0.2.2/24 | | | | | | | 192.0.2.3/24 |
| GW=192.0.2.4 | | | | | | | GW=192.0.2.4 |
| | | | | | | | +------+ |
| | | | | | | +----+ GW +-- |
| | | | | | | /+------+ |
| | | | | | | 192.0.2.4/24 |
| | | | | | | |
| DC West | | | IP/MPLS Backbone | | | DC East |
+------------------+ | | | | +------------------+
| +--------------------+ |
| |
VRF_A : V VRF_A : V
+------------+---------+--------+ +------------+---------+--------+
| Prefix | Nexthop |Protocol| | Prefix | Nexthop |Protocol|
+------------+---------+--------+ +------------+---------+--------+
|192.0.2.1/32|127.0.0.1| Direct | |192.0.2.1/32|127.0.0.1| Direct |
+------------+---------+--------+ +------------+---------+--------+
|192.0.2.2/32|192.0.2.2| Direct | |192.0.2.2/32| PE-1 | IBGP |
+------------+---------+--------+ +------------+---------+--------+
|192.0.2.3/32| PE-2 | IBGP | |192.0.2.3/32|192.0.2.3| Direct |
+------------+---------+--------+ +------------+---------+--------+
|192.0.2.4/32| PE-2 | IBGP | |192.0.2.4/32|192.0.2.4| Direct |
+------------+---------+--------+ +------------+---------+--------+
|192.0.2.0/24|192.0.2.1| Direct | |192.0.2.0/24|192.0.2.1| Direct |
+------------+---------+--------+ +------------+---------+--------+
| 0.0.0.0/0 | PE-2 | IBGP | | 0.0.0.0/0 |192.0.2.4| Static |
+------------+---------+--------+ +------------+---------+--------+
Figure 2: Inter-subnet Unicast Example (1)
As shown in Figure 2, only one data center (i.e., DC East) is
deployed with a default gateway (i.e., GW). PE-2 which is connected
to GW would either be configured with or learn from GW a default
route with next-hop being pointed to GW. Meanwhile, this route is
distributed to other PE routers (i.e., PE-1) as per normal [RFC4364]
operation. Assume host A sends an ARP request for its default
gateway (i.e., 192.0.2.4) prior to communicating with a destination
host outside of its subnet. Upon receiving this ARP request, PE-1
acting as an ARP proxy returns its own MAC address as a response.
Host A then sends a packet for Host B to PE-1. PE-1 tunnels such
packet towards PE-2 according to the default route learnt from PE-2,
which in turn forwards that packet to GW.
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+--------------------+
+------------------+ | | +------------------+
|VPN_A:192.0.2.1/24| | | |VPN_A:192.0.2.1/24|
| \ | | | | / |
| +------+ \ ++---+-+ +-+---++/ +------+ |
| |Host A+----+--+ PE-1 | | PE-2 +-+----+Host B| |
| +------+\ | ++-+-+-+ +-+-+-++ | /+------+ |
| 192.0.2.2/24 | | | | | | | | 192.0.2.3/24 |
| GW=192.0.2.4 | | | | | | | | GW=192.0.2.4 |
| +------+ | | | | | | | | +------+ |
|--+ GW-1 +----+ | | | | | | +----+ GW-2 +-- |
| +------+\ | | | | | | /+------+ |
| 192.0.2.4/24 | | | | | | 192.0.2.4/24 |
| | | | | | | |
| DC West | | | IP/MPLS Backbone | | | DC East |
+------------------+ | | | | +------------------+
| +--------------------+ |
| |
VRF_A : V VRF_A : V
+------------+---------+--------+ +------------+---------+--------+
| Prefix | Nexthop |Protocol| | Prefix | Nexthop |Protocol|
+------------+---------+--------+ +------------+---------+--------+
|192.0.2.1/32|127.0.0.1| Direct | |192.0.2.1/32|127.0.0.1| Direct |
+------------+---------+--------+ +------------+---------+--------+
|192.0.2.2/32|192.0.2.2| Direct | |192.0.2.2/32| PE-1 | IBGP |
+------------+---------+--------+ +------------+---------+--------+
|192.0.2.3/32| PE-2 | IBGP | |192.0.2.3/32|192.0.2.3| Direct |
+------------+---------+--------+ +------------+---------+--------+
|192.0.2.4/32|192.0.2.4| Direct | |192.0.2.4/32|192.0.2.4| Direct |
+------------+---------+--------+ +------------+---------+--------+
|192.0.2.0/24|192.0.2.1| Direct | |192.0.2.0/24|192.0.2.1| Direct |
+------------+---------+--------+ +------------+---------+--------+
| 0.0.0.0/0 |192.0.2.4| Static | | 0.0.0.0/0 |192.0.2.4| Static |
+------------+---------+--------+ +------------+---------+--------+
Figure 3: Inter-subnet Unicast Example (2)
As shown in Figure 3, in the case where each data center is deployed
with a default gateway, hosts will get ARP responses directly from
their local default gateways, rather than from their local PE routers
when sending ARP requests for their default gateways.
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+------+
+------+ PE-3 +------+
+------------------+ | +------+ | +------------------+
|VPN_A:192.0.2.1/24| | | |VPN_A:192.0.2.1/24|
| \ | | | | / |
| +------+ \ ++---+-+ +-+---++/ +------+ |
| |Host A+-------+ PE-1 | | PE-2 +------+Host B| |
| +------+\ ++-+-+-+ +-+-+-++ /+------+ |
| 192.0.2.2/24 | | | | | | 192.0.2.3/24 |
| GW=192.0.2.1 | | | | | | GW=192.0.2.1 |
| | | | | | | |
| DC West | | | IP/MPLS Backbone | | | DC East |
+------------------+ | | | | +------------------+
| +--------------------+ |
| |
VRF_A : V VRF_A : V
+------------+---------+--------+ +------------+---------+--------+
| Prefix | Nexthop |Protocol| | Prefix | Nexthop |Protocol|
+------------+---------+--------+ +------------+---------+--------+
|192.0.2.1/32|127.0.0.1| Direct | |192.0.2.1/32|127.0.0.1| Direct |
+------------+---------+--------+ +------------+---------+--------+
|192.0.2.2/32|192.0.2.2| Direct | |192.0.2.2/32| PE-1 | IBGP |
+------------+---------+--------+ +------------+---------+--------+
|192.0.2.3/32| PE-2 | IBGP | |192.0.2.3/32|192.0.2.3| Direct |
+------------+---------+--------+ +------------+---------+--------+
|192.0.2.0/24|192.0.2.1| Direct | |192.0.2.0/24|192.0.2.1| Direct |
+------------+---------+--------+ +------------+---------+--------+
| 0.0.0.0/0 | PE-3 | IBGP | | 0.0.0.0/0 | PE-3 | IBGP |
+------------+---------+--------+ +------------+---------+--------+
Figure 4: Inter-subnet Unicast Example (3)
Alternatively, as shown in Figure 4, PE routers themselves could be
directly configured as default gateways of their locally connected
hosts as long as these PE routers have routes for outside networks.
3.2. Multicast
To support IP multicast between hosts of the same Virtual Subnet,
MVPN technologies [RFC6513] could be directly used without any
change. For example, PE routers attached to a given VPN join a
default provider multicast distribution tree which is dedicated for
that VPN. Ingress PE routers, upon receiving multicast packets from
their local hosts, forward them towards remote PE routers through the
corresponding default provider multicast distribution tree. Note
that here the IP multicast doesn't include link-local multicast.
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3.3. Host Discovery
PE routers should be able to discover their local hosts and keep the
list of these hosts up to date in a timely manner so as to ensure the
availability and accuracy of the corresponding host routes originated
from them. PE routers could accomplish local host discovery by some
traditional host discovery mechanisms using ARP or ND protocols.
3.4. ARP/ND Proxy
Acting as an ARP or ND proxies, a PE routers should only respond to
an ARP request or Neighbor Solicitation (NS) message for a target
host when it has a best route for that target host in the associated
VRF and the outgoing interface of that best route is different from
the one over which the ARP request or NS message is received. In the
scenario where a given VPN site (i.e., a data center) is multi-homed
to more than one PE router via an Ethernet switch or an Ethernet
network, Virtual Router Redundancy Protocol (VRRP) [RFC5798] is
usually enabled on these PE routers. In this case, only the PE
router being elected as the VRRP Master is allowed to perform the
ARP/ND proxy function.
3.5. Host Mobility
During the VM migration process, the PE router to which the moving VM
is now attached would create a host route for that host upon
receiving a notification message of VM attachment (e.g., a gratuitous
ARP or unsolicited NA message). The PE router to which the moving VM
was previously attached would withdraw the corresponding host route
when receiving a notification message of VM detachment (e.g., a VDP
message about VM detachment). Meanwhile, the latter PE router could
optionally broadcast a gratuitous ARP or send an unsolicited NA
message on behalf of that host with source MAC address being one of
its own. In this way, the ARP/ND entry of this host that moved and
which has been cached on any local host would be updated accordingly.
In the case where there is no explicit VM detachment notification
mechanism, the PE router could also use the following trick to
determine the VM detachment event: upon learning a route update for a
local host from a remote PE router for the first time, the PE router
could immediately check whether that local host is still attached to
it by some means (e.g., ARP/ND PING and/or ICMP PING). It is
important to ensure that the same MAC and IP are associated to the
default gateway active in each data center, as the VM would most
likely continue to send packets to the same default gateway address
after migrated from one data center to another. One possible way to
achieve this goal is to configure the same VRRP group on each
location so as to ensure the default gateway active in each data
center share the same virtual MAC and virtual IP addresses.
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3.6. Forwarding Table Scalability on Data Center Switches
In a Virtual Subnet environment, the MAC learning domain associated
with a given Virtual Subnet which has been extended across multiple
data centers is partitioned into segments and each segment is
confined within a single data center. Therefore data center switches
only need to learn local MAC addresses, rather than learning both
local and remote MAC addresses.
3.7. ARP/ND Cache Table Scalability on Default Gateways
When default gateway functions are implemented on PE routers as shown
in Figure 4, the ARP/ND cache table on each PE router only needs to
contain ARP/ND entries of local hosts As a result, the ARP/ND cache
table size would not grow as the number of data centers to be
connected increases.
3.8. ARP/ND and Unknown Uncast Flood Avoidance
In a Virtual Subnet environment, the flooding domain associated with
a given Virtual Subnet that has been extended across multiple data
centers, is partitioned into segments and each segment is confined
within a single data center. Therefore, the performance impact on
networks and servers imposed by the flooding of ARP/ND broadcast/
multicast and unknown unicast traffic is alleviated.
3.9. Path Optimization
Take the scenario shown in Figure 4 as an example, to optimize the
forwarding path for the traffic between cloud users and cloud data
centers, PE routers located at cloud data centers (i.e., PE-1 and PE-
2), which are also acting as default gateways, propagate host routes
for their own local hosts respectively to remote PE routers which are
attached to cloud user sites (i.e., PE-3). As such, the traffic from
cloud user sites to a given server on the Virtual Subnet which has
been extended across data centers would be forwarded directly to the
data center location where that server resides, since the traffic is
now forwarded according to the host route for that server, rather
than the subnet route. Furthermore, for the traffic coming from
cloud data centers and forwarded to cloud user sites, each PE router
acting as a default gateway would forward the traffic according to
the best-match route in the corresponding VRF. As a result, the
traffic from data centers to cloud user sites is forwarded along an
optimal path as well.
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4. Limitations
4.1. Non-support of Non-IP Traffic
Although most traffic within and across data centers is IP traffic,
there may still be a few legacy clustering applications which rely on
non-IP communications (e.g., heartbeat messages between cluster
nodes). Since Virtual Subnet is strictly based on L3 forwarding,
those non-IP communications cannot be supported in the Virtual Subnet
solution. In order to support those few non-IP traffic (if present)
in the environment where the Virtual Subnet solution has been
deployed, the approach following the idea of "route all IP traffic,
bridge non-IP traffic" could be considered. That's to say, all IP
traffic including both intra-subnet and inter-subnet would be
processed by the Virtual Subnet process, while the non-IP traffic
would be resorted to a particular Layer 2 VPN approach. Such unified
L2/L3 VPN approach requires ingress PE routers to classify the
traffic received from hosts before distributing them to the
corresponding L2 or L3 VPN forwarding processes. Note that more and
more cluster vendors are offering clustering applications based on
Layer 3 interconnection.
4.2. Non-support of IP Broadcast and Link-local Multicast
As illustrated before, intra-subnet traffic is forwarded at Layer 3
in the Virtual Subnet solution. Therefore, IP broadcast and link-
local multicast traffic cannot be supported by the Virtual Subnet
solution. In order to support the IP broadcast and link-local
multicast traffic in the environment where the Virtual Subnet
solution has been deployed, the unified L2/L3 overlay approach as
described in Section 4.1 could be considered as well. That's to say,
the IP broadcast and link-local multicast would be resorted to the
L2VPN forwarding process while the routable IP traffic would be
processed by the Virtual Subnet process.
4.3. TTL and Traceroute
As illustrated before, intra-subnet traffic is forwarded at Layer 3
in the Virtual Subnet context. Since it doesn't require any change
to the TTL handling mechanism of the BGP/MPLS IP VPN, when doing a
traceroute operation on one host for another host (assuming that
these two hosts are within the same subnet but are attached to
different sites), the traceroute output would reflect the fact that
these two hosts within the same subnet are actually connected via an
Virtual Subnet, rather than a Layer 2 connection since the PE routers
to which those two host are connected respectively would be displayed
in the traceroute output. In addition, for any other applications
which generate intra-subnet traffic with TTL set to 1, these
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applications may not be workable in the Virtual Subnet context,
unless special TTL processing for such case has been implemented
(e.g., if the source and destination addresses of a packet whose TTL
is set to 1 belong to the same extended subnet, neither ingress nor
egress PE routers should decrement the TTL of such packet.
Furthermore, the TTL of such packet should not be copied into the TTL
of the transport tunnel and vice versa).
5. Acknowledgements
Thanks to Susan Hares, Yongbing Fan, Dino Farinacci, Himanshu Shah,
Nabil Bitar, Giles Heron, Ronald Bonica, Monique Morrow, Rajiv Asati,
Eric Osborne, Thomas Morin, Martin Vigoureux, Pedro Roque Marque, Joe
Touch and Wim Henderickx for their valuable comments and suggestions
on this document. Thanks to Loa Andersson for his WG LC review on
this document. Thanks to Alvaro Retana for his AD review on this
document. Thanks to Ronald Bonica for his RtgDir review.
6. IANA Considerations
There is no requirement for any IANA action.
7. Security Considerations
This document doesn't introduce additional security risk to BGP/MPLS
IP VPN, nor does it provide any additional security feature for BGP/
MPLS IP VPN.
8. References
8.1. Normative References
[RFC0925] Postel, J., "Multi-LAN address resolution", RFC 925,
DOI 10.17487/RFC0925, October 1984,
<http://www.rfc-editor.org/info/rfc925>.
[RFC1027] Carl-Mitchell, S. and J. Quarterman, "Using ARP to
implement transparent subnet gateways", RFC 1027,
DOI 10.17487/RFC1027, October 1987,
<http://www.rfc-editor.org/info/rfc1027>.
[RFC4364] Rosen, E. and Y. Rekhter, "BGP/MPLS IP Virtual Private
Networks (VPNs)", RFC 4364, DOI 10.17487/RFC4364, February
2006, <http://www.rfc-editor.org/info/rfc4364>.
[RFC4389] Thaler, D., Talwar, M., and C. Patel, "Neighbor Discovery
Proxies (ND Proxy)", RFC 4389, DOI 10.17487/RFC4389, April
2006, <http://www.rfc-editor.org/info/rfc4389>.
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8.2. Informative References
[RFC4659] De Clercq, J., Ooms, D., Carugi, M., and F. Le Faucheur,
"BGP-MPLS IP Virtual Private Network (VPN) Extension for
IPv6 VPN", RFC 4659, DOI 10.17487/RFC4659, September 2006,
<http://www.rfc-editor.org/info/rfc4659>.
[RFC4761] Kompella, K., Ed. and Y. Rekhter, Ed., "Virtual Private
LAN Service (VPLS) Using BGP for Auto-Discovery and
Signaling", RFC 4761, DOI 10.17487/RFC4761, January 2007,
<http://www.rfc-editor.org/info/rfc4761>.
[RFC4762] Lasserre, M., Ed. and V. Kompella, Ed., "Virtual Private
LAN Service (VPLS) Using Label Distribution Protocol (LDP)
Signaling", RFC 4762, DOI 10.17487/RFC4762, January 2007,
<http://www.rfc-editor.org/info/rfc4762>.
[RFC5798] Nadas, S., Ed., "Virtual Router Redundancy Protocol (VRRP)
Version 3 for IPv4 and IPv6", RFC 5798,
DOI 10.17487/RFC5798, March 2010,
<http://www.rfc-editor.org/info/rfc5798>.
[RFC6513] Rosen, E., Ed. and R. Aggarwal, Ed., "Multicast in MPLS/
BGP IP VPNs", RFC 6513, DOI 10.17487/RFC6513, February
2012, <http://www.rfc-editor.org/info/rfc6513>.
[RFC6820] Narten, T., Karir, M., and I. Foo, "Address Resolution
Problems in Large Data Center Networks", RFC 6820,
DOI 10.17487/RFC6820, January 2013,
<http://www.rfc-editor.org/info/rfc6820>.
Authors' Addresses
Xiaohu Xu
Huawei
Email: xuxiaohu@huawei.com
Robert Raszuk
Mirantis Inc.
Email: robert@raszuk.net
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Christian Jacquenet
Orange
Email: christian.jacquenet@orange.com
Truman Boyes
Bloomberg LP
Email: tboyes@bloomberg.net
Brendan Fee
Extreme Networks
Email: bfee@extremenetworks.com
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