IDR W. Hao
S. Zhuang
Z. Li
Internet Draft Huawei Technologies Ltd.
Intended status: Standards Track
Expires: January 2016 July 6, 2015
Dissemination of Flow Specification Rules for NVO3
draft-hao-idr-flowspec-nvo3-00.txt
Abstract
This document defines BGP flow-spec extension for NVO3. A Flag in
BGP Path Attribute is introduced to indicate the Flow-spec rules
imposing on NVO3 outer or inner layer. A new subset of NVO3 specific
component types and extended community also are defined.
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Table of Contents
1. Introduction ................................................ 2
2. Use cases ................................................... 3
2.1. Flow-spec in Data Center................................ 3
2.2. Flow-spec for Data Center Interconnection............... 4
2.3. Requirements Summary.................................... 5
3. The Flow Specification encoding for NVO3..................... 5
4. The Flow Specification Traffic Actions for NVO3.............. 6
5. Security Considerations...................................... 7
6. IANA Considerations ......................................... 8
6.1. Normative References.................................... 8
6.2. Informative References.................................. 9
7. Acknowledgments ............................................. 9
1. Introduction
BGP Flow-spec is an extension to BGP that allows for the
dissemination of traffic flow specification rules. It leverages the
BGP Control Plane to simplify the distribution of ACLs, new filter
rules can be injected to all BGP peers simultaneously without
changing router configuration. The typical application of BGP Flow-
spec is to automate the distribution of traffic filter lists to
routers for DDOS mitigation.
RFC5575 defines a new BGP Network Layer Reachability Information
(NLRI) format used to distribute traffic flow specification rules.
NLRI (AFI=1, SAFI=133)is for IPv4 unicast filtering. NLRI (AFI=1,
SAFI=134)is for BGP/MPLS VPN filtering. The Flow specification match
part only includes single layer IP information like
source/destination prefix, protocol, ports, and etc, it can't be
used for overlay network like NVO3 directly.
In cloud computing era, multi-tenancy has become a core requirement
for data centers. Since NVO3 can satisfy multi-tenancy key
requirements, this technology is being deployed in an increasing
number of cloud data center network. NVO3 focuses on the
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construction of overlay networks that operate over an IP (L3)
underlay transport network. It can provide layer 2 bridging and
layer 3 IP service for each tenant. VXLAN and NVGRE are two typical
NVO3 encapsulations. GENEVE [draft-ietf-nvo3-geneve-00],GUE[draft-
ietf-nvo3-gue-01] and GPE [draft-ietf-nvo3-vxlan-gpe-00] are three
emerging NVO3 encapsulations in progress.
In NVO3 network, we also have requirements to deploy BGP Flow-spec
for DDoS attack traffic mitigation or for traffic steering. The Flow
specification rules in NVO3 network can be based on inner layer 2
Ethernet information, inner layer 3 IP information, outer layer 2
Ethernet information, outer layer 3 IP information, and/or NVO3
header information. However, current flow specification match part
only includes single layer Ethernet or IP information, it can't be
imposed on the NVO3 traffic directly due to lack of Flag to indicate
which layer should be filtered, current flow specification match
part also doesn't include the NVO3 header information.
This draft proposes a new subset of component types and extended
community to support the NVO3 flow-spec application.
2. Use cases
2.1. Flow-spec in Data Center
BGP Flow-spec can be used for DDOS mitigation and traffic steering
for service chaining in a data center. A centralized BGP Flowspec
speaker should be deployed in the data center.
When BGP Flow-spec is used for DDOS mitigation, the centralized
speaker also acts as a traffic analyzer. When the analyzer detects
abnormal traffic, it will automatically generate Flow-spec rules and
distribute it to remote BGP peers, i.e., the remote NVEs connecting
TSs or outside networks. Inner layer 2/3 information and VN ID
should be included as the match part. Traffic-rate and traffic-
marking are useful for simple attacks. However, for complicated
attacks, traffic-redirect should be used for DDOS traffic cleaning.
Currently traffic-redirect method only includes redirecting traffic
into a VRF by specifying the VPN RT value and redirecting to IP. If
the traffic cleaner is also attached to the NVO3 network,
redirecting traffic into a NVO3 tunnel will be more straightforward
to steer the abnormal traffic to the cleaner device attached to a
remote NVE.
When BGP Flow-spec is used for service chaining, the classification
rules is determined on the centralized speaker and is distributed to
each classifier to steer the traffic to a service function path
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(SFP). A SFP can be multiple segmented NVO3 tunnel stitched together
to forward the specific traffic through an ordered SFs. In this case,
redirecting traffic to a specified SFP should be enforced on the
classifier.
2.2. Flow-spec for Data Center Interconnection
+--+
|CE|
+--+
|
+----+
+----| PE |----+
+---------+ | +----+ | +---------+
+----+ | +---+ +---+ | +----+
|NVE1|--| | | | | |--|NVE3|
+----+ | |GW1| |GW3| | +----+
| +---+ +---+ |
| NVO-1 | MPLS | NVO-2 |
| +---+ +---+ |
| | | | | |
+----+ | |GW2| |GW4| | +----+
|NVE2|--| +---+ +---+ |--|NVE4|
+----+ +---------+ | | +---------+ +----+
+--------------+
Figure 1 NVO3 data center interconnection
The MPLS L2/L3 VPN in the WAN network can be used for NVO3 based
data center network interconnection. When the DC and the WAN are
operated by the same administrative entity, the Service Provider can
decide to integrate the GW and WAN Edge PE functions in the same
router for obvious CAPEX and OPEX saving reasons. This is
illustrated in Figure 1. There are two interconnection solutions as
follows:
1. End to end NVO3 tunnel across different data centers. NVE1 perform
NVO3 encapsulation for DCI interconnection with NVE3, the
destination VTEP IP is NVE3's IP. The GW doesn't perform NVO3
tunnel termination. The DCI WAN is pure underlay network.
2. Segmented NVO3 tunnels across different data centers. NVE1 doesn't
perform end to end NVO3 encapsulation to NVE3 for DCI
interconnection. The GW performs NVO3 tunnel encapsulation, and
then transmits the inner original traffic through MPLS network to
peer data center GW. The peer data center GW terminates MPLS
encapsulation in WAN network, and then uses another NVO3
encapsulation to transmit the traffic to local NVE3.
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In the first solution, to differentiate bandwidth and QOS among
different tenants or applications, different TE tunnels in the WAN
network will be used to carry the end to end NVO3 encapsulation
traffic using VN ID, NVO3 outer header DSCP and etc as traffic
classification match part. BGP Flow-spec can be used to set the
traffic classification.
In the second solution, a centralized BGP speaker can be deployed
for DDOS mitigation in the WAN network. When the analyzer detects
abnormal traffic, it will automatically generate Flow-spec rules and
distribute it to each GW, the match part should include inner or
outer L2/L3 layer or NVO3 header.
2.3. Requirements Summary
1. The match part should include inner L2/L3 header information and
NVO3 header.
2. The Traffic Filtering Actions supports redirect to TE tunnel or
NVO3 tunnel.
3. The Flow Specification encoding for NVO3
The NLRI format for this address family consists of a fixed-length
Route Distinguisher field (8 bytes) followed by a flow specification,
following the encoding defined in this document. The NLRI length
field shall include both the 8 bytes of the Route Distinguisher as
well as the subsequent flow specification.
Flow specification rules received via this NLRI apply only to
traffic that belongs to the VPN instance(s) in which it is imported.
Flow rules are accepted by default, when received from remote PE
routers.
Because NVO3 encapsulation includes outer layer 2/3 header, inner
layer 2/3 header and NVO3 header, inner and outer layer Flag is
introduced to indicate the Flow-spec rules imposing on outer or
inner layer. The component types defined in [RFC5575],[draft-ietf-
idr-flow-spec-v6-06] and [draft-ietf-idr-flowspec-l2vpn-01] combined
with the Flag indicator can be used for the NVO3 traffic filtering.
A bit in 'traffic action' is applied as the inner and outer layer
indicator.
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For NVO3 header part, the following additional component types are
introduced.
Type TBD1 - VN ID
Encoding: <type (1 octet), [op, value]+>
Defines a list of {operation, value} pairs used to match 24-bit VN
ID fields. VN ID is tenant identification in NVO3 network. Values
are encoded as 1- to 3-byte quantities.
Type TBD2 - NVO3 Proto Type
Encoding: <type (1 octet), [op, value]+>
Defines a list of {operation, value} pairs used to match 8-bit
Protocol Type fields. Values are encoded as 1-byte quantity.
Other types:
The additional types for GENEVE,GUE and GPE header specific part
will be added later.
4. The Flow Specification Traffic Actions for NVO3
40 41 42 43 44 45 46 47
+---+---+---+---+---+---+---+---+
| reserved | L | S | T |
+---+---+---+---+---+---+---+---+
Layer Flag(Bit 45): When this bit is set, the corresponding
filtering rules will be applied on the NVO3 inner layer. If not set,
the corresponding filtering rules will be applied on the NVO3 outer
layer.
+--------+--------------------+--------------------------+
| type | extended community | RFC or Draft |
+--------+--------------------+--------------------------+
| 0x8006 | traffic-rate | RFC5575 |
| 0x8007 | traffic-action | RFC5575 |
| 0x8008 | redirect | RFC5575 |
| 0x8009 | traffic-marking | RFC5575 |
| TBD | redirect to Tunnel | This draft |
+--------+--------------------+--------------------------+
Besides to support the above extended communities per RFC5575,
similar to 'redirect to IP' [REDIRECTIP], a new extended community
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of 'redirect to Tunnel' is requested for service chaining and
traffic steering. The sub-type value [to be assigned by IANA]
indicates that the global administrator and local administrator
fields encode a flow-spec 'redirect to tunnel' action. In the new
extended communities the 2-byte local administrator field is
formatted as shown in Figure 1.
0 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved |C|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2 : Local Administrator
In the local administrator field the least-significant bit is
defined as the 'C' (or copy) bit. When the 'C' bit is set the
redirection applies to copies of the matching packets and not to the
original traffic stream.
All bits other than the 'C' bit in the local administrator field
MUST be set to 0 by the originating BGP speaker and ignored by
receiving BGP speakers.
A set of tunnels can be specified in the BGP Path Attribute. In
[draft-rosen-idr-tunnel-encaps-00], the tunnel type and
encapsulation information of VXLAN, NVGRE, VXLAN-GPE and etc are
defined using Tunnel Encapsulation Attribute Sub-TLVs. In [draft-li-
idr-mpls-path-programming-01], the tunnel type and encapsulation
information of RSVP-TE, LDP, Segment Routing Path and etc are
defined using Extended Unicast Tunnel Attributes.
If a BGP speaker receives multiple flow-spec routes for the same
flow-spec NLRI and all of them are considered best and usable paths
according to the BGP speaker's multipath configuration and each one
carries one or more 'redirect to Tunnel' extended communities, the
BGP speaker SHOULD load-share the redirected packets across all the
Tunnels.
5. Security Considerations
No new security issues are introduced to the BGP protocol by this
specification.
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6. IANA Considerations
A bit in 'Traffic Action' is requested as the inner and outer layer
indicator for Flow-spec rules.
IANA is requested to create and maintain a new registry entitled:
"Flow spec NVO3 Component Types":
Type TBD1 - - VN ID
Type TBD2 - - NVO3 Proto Type
IANA is requested to update the reference for the following
assignment in the "BGP Extended Communities Type - extended,
transitive" registry:
Type value Name Reference
---------- ---------------------------------------- ---------
TBD Redirect to Tunnel [this document]
6.1. Normative References
[1] [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[2] [RFC5575] P. Marques, N. Sheth, R. Raszuk, B. Greene, J.Mauch,
D. McPherson, "Dissemination of Flow Specification Rules", RFC
5575, August 2009.
[3] [GENEVE] J. Gross, T. Sridhar, etc, " Geneve: Generic Network
Virtualization Encapsulation", draft-ietf-nvo3-geneve-00, May
2015.
[4] [GUE] T. Herbert, L. Yong, O. Zia, " Generic UDP
Encapsulation", draft-ietf-nvo3-gue-01, Jun 2015.
[5] [GPE] P. Quinn,etc, " Generic Protocol Extension for VXLAN",
draft-ietf-nvo3-vxlan-gpe-00, May 2015.
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6.2. Informative References
[1] [EVPN] Sajassi et al., "BGP MPLS Based Ethernet VPN", draft-
ietf-l2vpn-evpn-07.txt, work in progress, May, 2014.
[2] [REDIRECTIP] J. Uttaro et al., "BGP Flow-Spec Redirect to IP
Action", draft-ietf-idr-flowspec-redirect-ip-02.txt, work in
progress, Feb, 2015.
7. Acknowledgments
The authors wish to acknowledge the important contributions of Susan
Hares, Qiandeng Liang, Nan Wu.
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Authors' Addresses
Weiguo Hao
Huawei Technologies
101 Software Avenue,
Nanjing 210012
China
Email: haoweiguo@huawei.com
Shunwan Zhuang
Huawei Technologies
Huawei Bld., No.156 Beiqing Rd.
Beijing 100095
China
Email: zhuangshunwan@huawei.com
Zhenbin Li
Huawei Technologies
Huawei Bld., No.156 Beiqing Rd.
Beijing 100095
China
Email: lizhenbin@huawei.com
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