Understanding COR on Cisco IOS Gateways
The axiological apparatus at the centermost of the COR functionality relies on the definition
of admission and approachable corlists. Each corlist is authentic to accommodate a cardinal of
members, which are tags ahead authentic aural Cisco IOS. Assorted CORs are
defined, and corlists are configured that accommodate these CORs. Each corlist is again assigned
to punch aeon as an admission or approachable corlist.
When a alarm goes through the router, an admission punch associate and an approachable punch associate are
selected based on the Cisco IOS dial-peer acquisition logic. If corlists are associated with the
selected punch peers, the afterward added analysis is performed afore extending the call:
■ If the COR activated on an admission dial-peer (for admission calls) is a cool set or
equal to the COR activated to the approachable dial-peer (for approachable calls), the alarm goes
through.
■ If the COR activated on an admission dial-peer (for admission calls) is NOT a cool set
or according to the COR activated to the approachable dial-peer (for approachable calls), the alarm is
rejected.
Chapter 7: Configuring Advanced Punch Plans 421
Note Admission and approachable are agreement acclimated with account to the articulation ports. For example,
if you angle up a buzz to one of the FXS ports of a router and try to accomplish a call
from that phone, it is an admission alarm for the router/voice port. Similarly, if you accomplish a
call to that FXS phone, it is an approachable call.
If no corlist statements are activated to some punch peers, the afterward backdrop apply:
■ When no admission corlist is configured on a dial-peer, the absence admission corlist is
used. The absence admission corlist has the accomplished accessible priority, and it therefore
allows this dial-peer to admission all added dial-peers, behindhand of their approachable corlist.
■ When no approachable corlist is configured on a dial-peer, the absence approachable corlist is
used. The absence approachable corlist has the everyman accessible priority, and it therefore
allows all added dial-peers to admission this dial-peer, behindhand of their incoming
corlist.
COR Behavior Example
Figure 7-31 shows the behavior of COR.
422 Authorized Self-Study Guide Cisco Articulation over IP (CVOICE)
dial-peer articulation 1 voip
dial-peer articulation 2 pots
destination-pattern 1…
dial-peer articulation 3 pots
destination-pattern 2…
corlist admission c1
Member A
Member B
Member C
corlist approachable c2
corlist approachable c3
Member A
Member B
Member A
Member B
? Member D
1. Alarm 100
Dials 1XXX
2. Alarm 200
Dials 2XXX
Figure 7-31 COR Behavior
The VoIP punch associate is associated with the c1 admission corlist, with associates A, B, and C.
You can anticipate of associates of the admission corlist as “keys.”
The aboriginal POTS punch associate has a destination arrangement of 1... and is associated with the c2
outgoing corlist, with associates A and B. The additional POTS punch associate has a destination
pattern of 2.. and is associated with the c3 approachable corlist, with associates A, B, and D.
You can anticipate of associates of the approachable corlists as “locks.”
For the alarm to succeed, the admission corlist of the admission punch associate charge accept all the
“keys” bare to accessible all the “locks” of the approachable corlist of the approachable punch peer.
In the archetype apparent in the Figure 7-31, a aboriginal VoIP alarm with destination 100 is received
by the router. The Cisco IOS call-routing argumentation matches the admission alarm leg with the
VoIP punch associate and the approachable alarm leg with the aboriginal POTS punch peer. The COR argumentation is
then applied. Because the c1 admission corlist has all the keys bare for the c2 outgoing
corlist locks (A and B), the alarm succeeds.
A additional VoIP alarm with destination 200 is again accustomed by the router. The Cisco IOS
call-routing argumentation matches the admission alarm leg with the VoIP punch associate and the outgoing
call leg with the additional POTS punch peer. The COR argumentation is again applied. Because the c1
incoming corlist is missing one “key” for the c3 approachable corlist (D), the alarm is rejected.
Calling privileges on Cisco IOS gateways use two components, as illustrated in
Figure 7-32.
Chapter 7: Configuring Advanced Punch Plans 423
COR account INTL
911
Local
LD
INTL
COR account INTCall
INTL
COR account LOCAL
911
Local
Incoming COR account Approachable COR list
Individual
CORs
Figure 7-32 COR Components
The two apparatus are
■ COR: A COR is the architecture block of calling privileges.
■ corlist: A corlist contains assorted CORs and is apprenticed to punch peers.
When a alarm is routed, the aperture checks the corlist of the entering and the corlist of
the outbound punch peer. Table 7-7 reviews the assorted COR results, which depend on the
corlists applied, or not applied, to admission and/or approachable punch peers.
Table 7-7 Alarm Acquisition with Corlists
Corlist on Corlist on
Incoming Outgoing
Dial Associate Punch Associate Result Reason
No COR. No COR. Alarm succeeds. COR is not involved.
No COR. Corlist activated for Alarm succeeds. The admission punch peer, by
outgoing calls. default, has the accomplished COR priority
when no COR is applied.
Therefore, if you administer no COR
for an admission alarm leg to a dial
peer, this punch associate can accomplish calls
out of any added punch peer, regardless
of the COR agreement on
the approachable punch peer.
The corlist activated No COR. Alarm succeeds. The approachable punch peer, by
for admission calls. default, has the everyman priority.
Because there are some COR
configurations for admission calls
on the incoming, basic dial
peer, it is a superset of the outgoing
call COR configurations on
the outgoing, absolute dial
peer.
The corlist activated The corlist activated Alarm succeeds. The corlist for admission calls on
for admission calls. for approachable calls. the admission punch associate is a
(Superset of corlists (Subset of corlists superset of corlists for outgoing
applied for approachable activated for in- calls on the approachable punch peer.
calls on the approachable advancing calls on the
dial peer.) admission punch peer.)
The corlist activated for The corlist activated Alarm cannot Corlists for admission calls on the
incoming calls. for approachable calls. be completed admission punch associate are not a super
(Subset of corlists (Superset of corlists appliance this set of corlists for approachable calls
applied for approachable activated for in- approachable punch on the approachable punch peer.
calls on the approachable advancing calls on the peer.
dial peer.) admission punch peer.)
COR Example
Figure 7-33 illustrates the abstraction of COR on Cisco IOS gateways.
424 Authorized Self-Study Guide Cisco Articulation over IP (CVOICE)
Figure 7-33 COR Example
A archetypal appliance of COR is to ascertain a COR name for the cardinal that an outgoing
dial associate serves, again ascertain a account that contains alone that COR name, and accredit that list
as corlist approachable for this approachable punch peer. For example, the punch associate with destination
pattern 9011T can accept a corlist approachable that contains COR INTL, as apparent in
Figure 7-33.
In this example, four CORs are defined:
■ 911
■ Local
■ LD
■ INTL
The four CORs are acclimated to actualize three admission corlists that will be assigned to phones
and users:
■ Local: This corlist contains the CORs 911 and Local. This account will acquiesce users to
place emergency calls and bounded PSTN calls.
■ LD: This corlist contains the CORs 911, Local, and LD. This corlist will acquiesce users
to abode emergency calls, bounded calls, and continued ambit PSTN calls.
■ INTL: This corlist contains the CORs 911, Local, LD, and INTL. This corlist will
allow users to abode any PSTN call.
Chapter 7: Configuring Advanced Punch Plans 425
COR account INTCall
INTL
COR account Local
Incoming COR list
Outgoing COR list
COR account INTL
COR account LD
911
Local
911
Local
LD
INTL
911
Local
LD
Members International
LD Service
Provider
dial-peer articulation 9011 pots
destination-pattern 9011T
prefix 011
cor approachable INTcall
port 0/0:23
COR INTL is
included in COR list
INTL; alarm is routed.
0/0
Member
COR INTL is not
included in COR lists
Local or LD; calls
are blocked.
A corlist will be assigned to an approachable POTS punch associate acclimated to avenue all-embracing calls
to the all-embracing continued ambit account provider:
■ INTLCall: This corlist contains the COR INTL and will be acclimated for outbound INTL
PSTN calls.
When a alarm is baffled appliance the admission corlist INTL and is akin adjoin the outgoing
corlist INTLCall, the alarm succeeds because COR INTL is included in the corlist INTL.
When a alarm is baffled appliance the admission corlist Bounded and is akin adjoin the outgoing
corlist INTLCall, the alarm is blocked because COR INTL is not included in the corlist
Local.