This document discusses various concepts related to network virtualization. It begins by explaining virtual LANs (VLANs) and how they create broadcast domains on a physical network using VLAN tags. It then discusses how OpenFlow can implement more flexible VLAN support and how virtual private networks (VPNs) can provide private networks over public infrastructure using IPsec or MPLS. Network virtualization is defined as the ability to run multiple logical networks over a shared physical network. OpenDaylight's Virtual Tenant Network plugin provides multitenant virtual networks on a SDN using VLAN technology. The document concludes with a brief discussion of software-defined infrastructure.

1. Network
Virtualization
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2. Index
1. VIRTUAL LANS
2. OPENFLOW VLAN SUPPORT
3. VIRTUAL PRIVATE NETWORKS
4. NETWORK VIRTUALIZATION
5. OPENDAYLIGHT’S VIRTUAL TENANT NETWORK
6. SOFTWARE-DEFINED INFRASTRUCTURE
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5. 1. VIRTUAL LANS
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6. Virtual Local Area Network
(VLAN)
• A virtual network abstraction
on top of a physical packet-
switched network.
• A VLAN is essentially a
broadcast domain for a
specified set of switches.
• These switches are required
to be aware of the existence
of VLANs and configured
accordingly, to perform
switching of packets between
devices belonging to the
same VLAN.
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7. Defining VLANs
1. Membership by port group
2. Membership by MAC address
3. Membership based on protocol
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8. IEEE 802.1Q VLAN Standard
• VLAN is an administratively configured broadcast
domain, consisting of a subset of end stations
attached to a LAN.
• A VLAN is not limited to one switch but can span
multiple interconnected switches.
• In that case, traffic between switches must
indicate VLAN membership.
• This is accomplished in 802.1Q by inserting a tag
with a VLAN identifier (VID) with a value in the
range from 1 to 4094. Each VLAN in a LAN
configuration is assigned a globally unique VID.
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9. • A committee of the Institute of Electrical and
Electronics Engineers (IEEE) responsible for
developing standards for local and
metropolitan area networks (LANs).
1. User priority (3 bits): The priority level for this
frame.
2. Canonical format indicator (1 bit): Is always set
to 0 for Ethernet switches. CFI is used for
compatibility between Ethernet type networks
and Token Ring type networks.
3. VLAN identifier (12 bits): The identification of
the VLAN.
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10. 2. OPENFLOW VLAN SUPPORT
• OpenFlow, allows for much more flexible
management and control of VLANs.
• It should be clear how OpenFlow can set up
flow table entries for forwarding based on one
or both VLAN tags.
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11. 3. VIRTUAL PRIVATE NETWORKS
• A VPN is a private network that is configured
within a public network (a carrier’s network or
the Internet) to take advantage of the
economies of scale and management facilities
of large networks.
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12. • IP security (IPsec)
– The principal feature of IPsec that enables it to
support these varied applications is that it can
encrypt/authenticate traffic at the IP level.
– Therefore, all distributed applications, including
remote logon, client/server, e-mail, file transfer,
web access, and so on, can be secured.
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15. • Using IPsec to construct a
VPN has the following
benefits:
1. When IPsec is implemented
in a firewall or router, it
provides strong security that
can be applied to all traffic
crossing the perimeter.
2. IPsec in a firewall is resistant
to bypass if all traffic from
the outside must use IP and
the firewall is the only
means of entrance.
3. IPsec is below the transport
layer (TCP, UDP) and so is
transparent to applications.
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16. • MPLS
– Multiprotocol Label Switching (MPLS) is a set of (IETF)
specifications for including routing and traffic
engineering information in packets.
– MPLS comprises a number of interrelated protocols.
– It can be used in IP networks but also in other types of
packet-switching networks.
– MPLS is used to ensure that all packets in a particular
flow take the same route over a backbone.
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17. • In an MPLS network, a fixed-length label
encapsulates an IP packet or a data link frame.
• The MPLS label contains all the information
needed by an MPLS-enabled router to
perform routing, delivery, QoS, and traffic
management functions.
• An MPLS network or internet consists of a set
of nodes, called label switching routers (LSRs)
capable of switching and routing packets on
the basis of a label appended to each packet.
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18. • Labels define a flow of packets between two
endpoints or, in the case of multicast,
between a source endpoint and a multicast
group of destination endpoints.
• For each distinct flow, called a forwarding
equivalence class (FEC), a specific path
through the network of LSRs is defined, called
a label switched path (LSP).
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19. Key VPN terms
1. Attachment circuit (AC)
2. Customer edge (CE)
3. Layer 2 VPN (L2VPN)
4. Layer 3 VPN (L3VPN)
5. Packet switched network (PSN)
6. Provider edge (PE)
7. Tunnel
8. Tunnel multiplexer
9. Virtual channel (VC)
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20. Layer 2 MPLS VPN
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21. Layer 3 MPLS VPN
• Whereas L2VPNs are constructed based on link-
level addresses (for example, MAC addresses),
L3VPNs are based on VPN routes between CEs
based on IP addresses.
• An MPLS-based L3VPN typically uses a stack of
two labels. The inner label identifies a specific
VPN instance; the outer label identifies a tunnel
or route through the MPLS provider network.
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22. 4. NETWORK VIRTUALIZATION
1. Physical resource
2. Logical resource
3. Virtual resource
4. Virtual network
5. Network virtualization (NV)
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27. Benefits of Network Virtualization
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28. 5. OPENDAYLIGHT’S VIRTUAL TENANT
NETWORK
• Virtual Tenant Network (VTN) is an
OpenDaylight (ODL) plug-in developed by NEC.
• It provides multitenant virtual networks on an
SDN, using VLAN technology.
• The VTN abstraction functionality enables
users to design and deploy a virtual network
without knowing the physical network
topology or bandwidth restrictions.
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29. • VTN consists of two components
– VTN Manager
– VTN Coordinator
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31. 6. SOFTWARE-DEFINED INFRASTRUCTURE
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32. Reference
Foundations of Modern Networking: SDN,
NFV, QoE, IoT, and Cloud
by William Stallings
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33. Thank you
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