Transcript Juniper Networks Presentation Template-US

E-VPN and Data Center
R. Aggarwal ([email protected])
Copyright © 2004 Juniper Networks, Inc.
Proprietary and Confidential
www.juniper.net
1
Reference Model and Terminology
DCS1
DCS2
DCB3
DCB1
DCS8
Data Center 1
DCS5
Data Center 3
“WAN”
DCS4
DCB2
Data Center 2

DC: Data Center

DCS: Data center switch
DCB4/DCS9
Data Center 4
Client Site BR
Client site
• Connected to Servers/VMs

DCB: Data center border router
• Could be co-located with DCS

“WAN” provides interconnect among DCs, and between DCs
and Client Site BR
Copyright © 2004 Juniper Networks, Inc.
Proprietary and Confidential
www.juniper.net
2
Data Center Interconnect: Layer 2
Extension
DCB3
VM4
VM1
DCS1
VM2
DCS2
Data Center 1
DCS8
DCB1
Data Center 3
VM7
VM3
DCS4
DCS5
VM6
“WAN”
DCB4/DCS9
VM8
DCB2
Data Center 2
VM5
Data Center 4
Client Site BR

VLAN1 (subnet1) stretches between DC1,
DC2, DC3 and DC4
Client site


VLAN2 (subnet2) is present only on DCS1
VLAN3 (subnet3) stretches between DC1 and DC2

VLAN stretch is required for cloud computing “resource fungibility”, redundancy etc.

Communication between VMs on different VLANs/subnets and between clients
and the VMs requires layer 3 routing
Copyright © 2004 Juniper Networks, Inc.
Proprietary and Confidential
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3
BGP-MPLS E-VPNs for Data Center
Interconnect
 BGP-MPLS based technology, one application of which is data center
interconnect between data center switches for intra-VLAN forwarding i.e.,
layer 2 extension
 Why?
• Not all data center interconnect layer 2 extension requirements are
satisfied by existing MPLS technology such as VPLS
• E.g., minimizing flooding, active-active points of attachment, fast
edge protection, scale, etc.
 How?
• Reuses several building blocks from existing BGP-MPLS technologies
• Requires extensions to existing BGP-MPLS technologies
• Draft-raggarwa-sajassi-l2vpn-evpn-01.txt
• Being pursued in the L2VPN WG
Copyright © 2004 Juniper Networks, Inc.
Proprietary and Confidential
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4
E-VPN Reference Model
VPN A
Host -A1
MES 4
ESI 1,
VLAN1
VPN A
Host-A4
ESI 3, VLAN1
MES 2
EFI-A
ESI 1,
VLAN1
Host –A5
ESI 2,
VLAN2
MES 1
EFI-A
RR
EFI-A
ESI 4, VLAN2
EFI-B
ESI 5, VLAN1
Host-A3
EFI-B
VPN B
Ethernet
Switch-B3
VPN B
Host-B1
MES 3
VPN A

MES - MPLS Edge Switch; EFI – E-VPN Forwarding Instance; ESI – Ethernet
Segment Identifier (e.g., LAG identifier)

MESes are connected by an IP/MPLS infrastructure

Transport may be provided by MPLS P2P or MP2P LSPs and optionally
P2MP/MP2MP LSPs for “multicast”

Transport may be also be provided by IP/GRE Tunnels Proprietary and Confidential
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5
Relating EVPN Reference Model to Data
Center Interconnect Reference Model
DCS2
DCS1
DCB3
DCB1
Data Center 1
DCS4
“WAN”
DCS8
Data Center 3
DCS5
DCB4/DCS9
Data Center 4
DCB2
Data Center 2

DCSes may act as MPLS Edge Switches (MES)
• DCSes may interconnect with DCBs using E-VPN
• DCSes are connected to hosts i.e., VMs

DCBs must participate in E-VPN although they may perform only
MPLS switching

WAN routers may or may not participate in E-VPN

Following slides will describe an overview of E-VPN and then apply EVPN to data center interconnect
Copyright © 2004 Juniper Networks, Inc.
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6
E-VPN Local MAC Address Learning
 A MES must support local data plane learning using
vanilla ethernet learning procedures
• When a CE generates a data plane packet such as
an ARP request
 MESes may learn the MAC addresses of hosts in the
control plane using extensions to protocols that run
between the MES and the hosts
 MESes may learn the MAC addresses of hosts in the
management plane
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7
E-VPN Remote MAC Address Learning
 E-VPN introduces the ability for an MES to advertise
locally learned MAC addresses in BGP to other MESes,
using principles borrowed from IP VPNs
 E-VPN requires an MES to learn the MAC addresses of
CEs connected to other MESes in the control plane
using BGP
• Remote MAC addresses are not learned in the data
plane
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8
Remote MAC Address Learning in the BGP
Control Plane
Architectural Benefits

Increases the scale of MAC addresses and VLANs supported
• BGP capabilities such as constrained distribution, Route Reflectors, inter-AS
etc., are reused

Allows hosts to connect to multiple active points of attachment

Improves convergence in the event of certain network failures

Allow hosts to relocate within the same subnet without requiring renumbering

Minimizes flooding of unknown unicast packets

Minimizes flooding of ARP
• Rest of the presentation will focus on this

Control over which MAC addresses are learned by which devices
• Simplifies operations; enables flexible topologies etc.
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9
ARP Scaling Optimization: Approach
 Minimize the radius of ARP request/response propagation
• Minimize the propagation radius of ARP request from a
server/Virtual Machine
• In the switching infrastructure in the data center
• Across data centers
• Respond to an ARP request from a server/VM as close to
the server/VM as possible
 Requires a number of components
• See the following slide
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ARP Scaling Optimization: Proxy ARP
 A network node as close to the server/VM, as possible,
performs “Proxy ARP” in response to ARP requests from the
server/VM
• The network node should ideally be the DCS
 Which MAC address does the network node use to respond
to the ARP request?
• The answer depends on the forwarding paradigm used
by the node to forward packets within the VLAN
• MAC lookup based forwarding within the VLAN/subnet
– The solution in the following slides focuses on this
• IP address based forwarding within the VLAN/subnet
– Not discussed in the following slides
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11
ARP Scaling Optimization: The Role of E- VPN (1)
When MAC lookup based forwarding is used within a
VLAN/subnet
 MESes perform Proxy ARP
 An MES responds to an ARP request, for an IP
address, with the MAC address bound to the IP
address
• When the destination is in the same subnet as
the sender of the ARP request
• The ARP request is not forwarded to other
MESes
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ARP Scaling Optimization: The Role of E- VPN (2)
 How does the MES learn the IP address bound to the MAC
address when the MAC address is remote?
• BGP MAC routes carry the IP address bound to the MAC
address
 How does an MES learn the IP to MAC binding when the
MAC address is local?
• Control or management plane between MES and CEs or
data plane snooping
 An MES advertises the local IP to MAC bindings in the MAC
routes
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Proprietary and Confidential
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