Table Of Contents
Virtual Private Networks "VPNs"
Technology Description
VPN
Inventory and Information Model Objects (IMOs)
Virtual Routing Forwarding (VRF) Entity
Equivalent Routing Entry
Virtual Routing Entry
Multi Protocol BGP Entity
Equivalent Cross Virtual Routing Entry
Cross Virtual Routing Entry
Network Topology
Service Alarms
Virtual Private Networks "VPNs"
This chapter describes the level of support that Cisco ANA provides for VPNs, as follows:
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Technology Description
•
Inventory and Information Model Objects (IMOs)
•
Network Topology
•
Service Alarms
Technology Description
VPN
BGP/MPLS VPNs, as defined in RFC 2547 and related drafts and standards, provide a Layer 3 VPN. With Layer 3 VPNs, each Provider Edge (PE) device acts like a set of virtual routers, one per VPN. The network provider configures the VPN membership of each PE router interface. In most cases, one port is used for multiple interfaces where each is associated with different VPNs. The port's view of the network is restricted to the VPNs of which it is a member, and it cannot address devices outside that environment. Either static routes are provisioned on both the Customer Edge (CE) and PE, or, for more complex scenarios, a routing protocol (such as RIP, OSPF or BGP) is run between CE and PE. So the interface between the CE and PE devices is conventional IP routing.
The network provider also establishes a suitable mesh of MPLS Label Switched Paths (LSPs) between all the PE routers that need to communicate. The PE devices qualify each external IP address that they learn with a per VPN identifier, and broadcast them to all other PE routers using an extended form of BGP depending on BGP connectivity. They also include an MPLS label that is specific to the destination route (or, in some implementations, the destination port). Through this process, the PE devices build up a complete map of the VPNs and destination labels.
The PE routers then use this information to route the packets across the backbone network to the correct destination within the relevant VPN.
Inventory and Information Model Objects (IMOs)
This section includes the following tables:
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Virtual Routing Forwarding (VRF) Entity (IVrf)
•
Equivalent Routing Entry (IRoutingEntries)
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Virtual Routing Entry (IVrfEntry)
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Multi Protocol BGP Entity (IMpBgp)
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Equivalent Cross Virtual Routing Entry (ICrossVrf)
•
Cross Virtual Routing Entry (ICrossVrfRoutingEntry)
Virtual Routing Forwarding (VRF) Entity
The following Virtual Routing Forwarding (VRF) Entity object describes the routing and address resolution protocols independent forwarding component of a MPLS-BGP based VPN router, which is bound by its Logical Sons attribute to all Network layer IP Interface objects, which IP Packets are being routed between, by this Virtual Routing Forwarding Entity.
Table 14-1 Virtual Routing Forwarding (VRF) Entity (IVrf)
Attribute Name
|
Attribute Description
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Virtual Routing Table
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Array of Equivalent Routing Entries
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Exported Route Targets
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Array of route target identifiers
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Imported Route Targets
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Array of route target identifiers
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Route Distinguisher
|
Route distinguisher
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ARP Entity
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Address Resolution Entity (ARP Entity) (see Internet Protocol "IP")
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Name
|
VRF name
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Logical Sons
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Array of all IP Interfaces, which IP packets are being routed between, by this Virtual Routing Forwarding (VRF) Entity
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Equivalent Routing Entry
The following Equivalent Routing Entry and Virtual Routing Entry objects describe a routing table's entries, each as an array of Virtual Routing Entries sharing a single IP Subnetwork destination.
Table 14-2 Equivalent Routing Entry (IRoutingEntries)
Attribute Name
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Attribute Description
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Routing Entries
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Array of Virtual Routing Entries (sharing a single destination)
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Virtual Routing Entry
Table 14-3 Virtual Routing Entry (IVrfEntry)
Attribute Name
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Attribute Description
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Next Hop BGP Address
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Next hop BGP IP address
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Incoming and Outgoing Inner Label
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Incoming and outgoing inner MPLS label
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Outer Label
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Outer MPLS label
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Destination IP Subnet
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Final destination IP subnet
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Next Hop IP Address
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Next hop IP address
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Type
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Route entry type (Null, Other, Invalid, Direct, Indirect, Static)
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Routing Protocol Type
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Routing protocol type (Null, Other, "Local, Network Managed, ICMP, EGP, GGP, Hello, RIP, IS-IS, ES-IS, Cisco IGRP, BBN SPF IGP, OSPF, BGP, EIGRP)
|
Outgoing Interface Name
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Outgoing IP interface name
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Multi Protocol BGP Entity
The following Multi Protocol BGP Entity object describes the BGP component of a MPLS-BGP based VPN router, which is bound by its Logical Sons attribute to all Virtual Routing Forwarding (VRF) Entity objects, which IP Packets are being routed between by this Multi Protocol BGP Entity.
Equivalent Cross Virtual Routing Entry
The following Equivalent Cross Virtual Routing Entry and Cross Virtual Routing Entry objects describe the first dimension of a cross virtual routing table, as an array of Cross Virtual Routing Entries sharing a single Virtual Routing Forwarding (VRF) Entity destination.
Table 14-5 Equivalent Cross Virtual Routing Entry (ICrossVrf)
Attribute Name
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Attribute Description
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Virtual Routing Entries
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Array of Cross Virtual Routing Entries (sharing a single destination)
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Virtual Routing Entity Name
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Virtual Routing Entity (VRF) name
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Cross Virtual Routing Entry
Table 14-6 Cross Virtual Routing Entry (ICrossVrfRoutingEntry)
Attribute Name
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Attribute Description
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Outgoing Virtual Routing Entity Identifier
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Outgoing virtual routing entity Object Identifier (OID)
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Incoming and Outgoing Virtual Routing Tags
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Incoming and outgoing virtual routing tags
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Destination IP Subnet
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Final destination IP subnet
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Next Hop IP Address
|
Next hop IP address
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Type
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Route entry type (Null, Other, Invalid, Direct, Indirect, Static)
|
Routing Protocol Type
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Routing protocol type (Null, Other, "Local, Network Managed, ICMP, EGP, GGP, Hello, RIP, IS-IS, ES-IS, Cisco IGRP, BBN SPF IGP, OSPF, BGP, EIGRP)
|
Outgoing Interface Name
|
Outgoing IP interface name
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Network Topology
The discovery of MPLS-BGP based Virtual Private (VPN) network topology is done by searching for the existence of the local Virtual Routing Forwarding (VRF) Entity's imported route targets in any remote side's VRF entity exported route targets.
Service Alarms
The following alarm is supported for this technology:
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Duplicate IP on VPN Found/Duplicate IP on VPN Fixed
Note
This alarm is disabled by default.
Note
For a detailed description of these alarms and for information about correlation see the Cisco Active Network Abstraction Fault Management User Guide, 3.6.