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MultiPop Scenario
The MultiPop scenario illustrates a configuration
that involves two POPs: Montreal and Ottawa. This configuration does
not provide redundancy. The NIC proxy communicates with the back office
host (BackOffice), which in turn communicates with the POP hosts (MontrealHost
and OttawaHost). Hosts MontrealHost and OttawaHost support equivalent
hosts and agents and manage resolutions in the same way.
When host BackOffice receives a data key from the
NIC proxy, the following sequence of events occurs:
- Host BackOffice forwards requests as follows:
- If the request is for the Montreal POP, host BackOffice
forwards the request to POP host MontrealHost.
- If the request is for the Ottawa POP, host BackOffice
forwards the request to POP host OttawaHost.
- Delegating tasks to other resolvers as necessary, the
resolvers in the POP obtain data values that correspond to the data
key request, and return them.
- The POP host returns the data values to host BackOffice,
which returns the value to the NIC proxy.
The scenario shows three realms for this
configuration:
Each realm provides a different type of
resolution. The following sections provide information about these
realms.
Figure 47 illustrates this
configuration.
Figure 47: MultiPop Configuration

IP Realm
This realm accommodates the situation in which
IP address pools are configured locally on each VR. The resolution
process takes a subscriber’s IP address as the key and returns
a reference to the SAE managing this subscriber as the value. This
realm uses essentially the same resolution process as the ip realm
for the OnePop scenario (see Figure 15). However,
some of the constraints differ.
The following agents interact with the resolvers
in this realm:
- Directory agents montrealPoolVr and ottawaPoolVr collect
and publish information that maps IP address pools to VRs. Each agent
publishes only the information that is relevant to its POP. You achieve
selective publishing by relating an Ottawa scope to the VRs in the
Ottawa POP and a Montreal scope to the VRs in the Montreal POP and
defining a search filter for the agents to load only the VRs in its
POP.
- Directory agent VrSaeId in the back office collects and
publishes information that maps VRs to SAEs for both POPs.
When the NIC proxy sends a subscriber’s IP
address to host BackOffice, the following sequence of events occurs:
- Host BackOffice passes the IP address to resolver ip/A1.
- Resolver ip/A1 obtains an IP pool for the IP address.
- Resolver ip/A1, based on the value of the IpPool, forwards
the request to ip/B1montreal or ip/B1ottawa.
- Resolver ip/B1montreal or resolver ip/B1ottawa obtains
a VR name for this IP pool and returns the VR name to resolver ip/A1.
- Resolver ip/A1 forwards the VR name to resolver ip/C1.
- Resolver ip/C1 obtains the SAE identity for this VR and
returns the value to resolver ip/A1.
- Resolver ip/A1 returns the SAE reference to its host.
- Host BackOffice returns the SAE reference to the NIC proxy.
Figure 48 illustrates the
interactions of the NIC components for this realm.
Figure 48: iP Realm for MultiPop Configuration

Shared IP Realm
This realm accommodates the situation in which
IP address pools are shared by VRs in the same POP. The realm takes
a subscriber’s IP address as the key and returns the corresponding
SAE as the value. Figure 16 shows the resolution
graph for this realm.
The following agents interact with resolvers in
this realm:
- Directory agents montrealPoolVr and ottawaPoolVr collect
and publish information about the mappings of IP address pools to
VRs. Each agent publishes only the information that is relevant to
its POP.
- SAE plug-in agents montrealIpVr and ottawaIpVr collect
and publish information about the mappings of subscriber IP addresses
to VRs. Each agent publishes only the information that is relevant
to its POP.
- Directory agent VrSaeId in the back office collects and
publishes information about the mappings of VRs to SAEs for both POPs.
When the NIC proxy sends a subscriber’s IP
address to host BackOffice, the following sequence of events occurs:
- Host BackOffice passes the IP address to resolver sharedIp/A1.
- Resolver sharedIp/A1 obtains an IP pool for the IP address.
- Resolver sharedIp/A1, based on the value of the IP pool,
forwards the request to sharedIp/B1montreal or sharedIp/B1ottawa.
- Resolver sharedIp/B1montreal or resolver sharedIp/B1ottawa
obtains a VR name for this IP address and returns the VR name to resolver
sharedIp/A1.
- Resolver sharedIp/A1 forwards the VR name to resolver
sharedIp/C1.
- Resolver sharedIp/C1 obtains the SAE identity for this
VR and returns the value to resolver sharedIp/A1.
- Resolver sharedIp/A1 passes the SAE reference to its host.
- Host BackOffice returns the SAE reference to the NIC proxy.
Figure 49 illustrates the
interactions of the NIC components for this realm.
Figure 49: sharedIP Realm for MultiPop Configuration

DN Realm
The DN realm takes the DN of an access subscriber
(an access DN) as the key and returns the corresponding SAE as the
value. Figure 50 shows the resolution process for this realm.
Figure 50 shows the resolution
graph for this realm.
Figure 50: Resolution Graph for MultiPOP dn Realm

The following agents interact with resolvers in
this realm:
- Directory agents ottawaEnterprise and montrealEnterprise
collect and publish information about the DNs of enterprise subscribers
(enterprise DNs). Each agent publishes only the information that is
relevant to its POP. You achieve selective publishing by relating
an Ottawa service scope to the enterprises in the Ottawa POP and a
Montreal service scope to the enterprises in the Montreal POP and
defining a search filter for the agents to load only the enterprises
in its POP.
- SAE plug-in agents montrealDnVr and ottawaDnVr collect
and publish information about the mappings of access DNs to VRs. Each
agent publishes only the information that is relevant to its POP.
- Directory agent VrSaeId collects and publishes information
about the mappings of VRs to SAEs for both POPs.
When the NIC proxy sends an access DN to host BackOffice,
the following sequence of events occurs:
- Host BackOffice passes the access DN to resolver dn/A1.
- Resolver dn/A1 obtains an enterprise DN for the access
DN.
- Resolver dn/A1, based on the value of the enterprise DN,
forwards the request to dn/B1montreal or dn/B1ottawa.
- Resolver dn/B1montreal or resolver dn/B1ottawa obtains
a VR name for this enterprise DN and returns the VR name to resolver
dn/A1.
- Resolver dn/A1 forwards the VR name to resolver dn/C1.
- Resolver dn/C1 obtains the SAE reference for this VR and
returns the value to resolver dn/A1.
- Resolver dn/A1 passes the SAE reference to its host.
- Host BackOffice returns the SAE reference to the NIC proxy.
Figure 51 illustrates the
interactions of the NIC components for this realm.
Figure 51: dn Realm for MultiPop Configuration

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