ASPIRANT

CVoice – CBT Nuggets 2

sethuvignesh — Sun, 31 Jul 2011 17:42:11 +0000

PBX will be connected to CO office Telco switches for PSTN connectivity and PBX at different branch offices will be inter-connected via Tie Lines for interoffice connectivity. The line from PBX to CO office is called CO trunk.

CO provides the following

* Manages Local loop – Local loop takes care of providing services for an area. A long cable will run over the entire area and the phones at the houses are connected to local loop.

*Call routing - CO for that area will inturn get connected to an other area CO to provide connectivity to other areas.

*Battery – Provides power to the phones though there is a power outage.

*Ring Generator – (-)48DC voltage will be used by the phone. When a phone goes off-hook a negative 48V dc voltage flows. When there is a circuit down on a phone, still the phone can ring bcoz Ring generator uses AC voltage which is sent to the phone to make it ring.

*Dial Tone – When Phone goes off-hook, the circuit on the phone closes which inturn informs CO to send the dial tone.

*Record Digits – When digits are dialled, the CO records it and provides the call routing.

PBX provides the following

*Control Complex – brain of PBX, used for route functions, call processing, dial tone generation etc-

* Line cards – cards that connect to the IP phones directly or thru the patch panel.

* Switch Backplane – responsible for making connections/paths between devices based on the control from control complex

* Powersupply /Fans

* Trunk cards – cards where the E1/T1 (PSTN) lines terminate and each line has 24 channel and each channel is of 64kbps. Each voice call over PSTN lines is 64kbps.

PBX Vs Key System

*PBX Supports digital phones/keysystem supports Analog & digital phones.

*PBX supports more than 50+ users/Keysystem supports users less than 50

* PBX acts a CO switch where calls inside office will not required to connect to CO trunk/Key system acts a typical shared line

*PBX uses digits “9″ or “0″ to connect CO trunk(outside office)/Key system uses line button for outside line

Analog phone Vs digital Phone

Analog phone uses Pulse dialing and digital phone uses Dual tone multifrequency (DTMF) dialing.

TDM Multiplexing: Digital Lines T1/E1 or BRI/PRI are used. T1 and PRI are same kind of lines but the type of signal used for control channel differs. The type of signal can be CAS(Channel Associated Signalling/Robbed bit signalling) when T1 is used and CCS (Common Channel Signalling) when PRI is used. The type of line used is determined the CO/PBX vendor. Robbed bit signalling means a single bit out of 64kbps of every time slot is used for control signal and in CCS an entire channel is used for control signal, so only 23 channel is available for Voice call. This kind of multiplexing is used in digital environment.

FDM(Frequency division Multiplexing): Used in Analog environment. The local loop from CO to home uses this FDM, meaning Phone,internet,cable tv uses the same wire but the signal are differentiated based on the frequency.

CVoice – CBT Nuggets 1

sethuvignesh — Tue, 26 Jul 2011 17:22:38 +0000

AVVID – Architecture for Voice, Video and Integrated Data, meaning Video/Voice/Data are integrated into IP packets and sent over the same link used for transferring data.

Cost Savings – Moves, ADDs, Changes, meaning if a phone is changed from one place to another during good old days, phone and PBX system has to be configured every time when they are moved. But VOIP set up does not requite such kind of configuration when there is a Move. Reduced wiring- no need of separate cabling for voice and data at switch end, single cable from switch to phone and a the from phone to PC. Reduced Branch office expense – instead of going for a separate link for voice in branch offices, existing data Network can be utilized and also Tie Lines between Branch offices. Application consolidation – meaning, hotel check out, check in, room service and all the applications will be accessed using same phone used in the hotel. Free Long distance – Nothing but CUG for voice connectivity between office at different geographical locations.Single inbox for messages like voice mail, fax, Extension Mobility, Internet website integration - online transactions using voice (Bank IVR), Open Architecture -architecture for mutli vendor integration.

Phase 1 Migration - Voice packets are transmitted over MPLS links instead of PSTN, but still old PBX and old Key system will be in place. Dependent on QOS. When transmitting over PSTN, 64kbps of traffic is BW is utilized but when transmitted over VOIP only 12kbps of voice BW is used.

Phase 2 Migration – Old PBX and Key sytem are removed and CCM is placed instead of them.

Understanding of CCM Setup

sethuvignesh — Sat, 26 Mar 2011 11:58:58 +0000

This post is to remind me of the current CCM setup at my office. The setup at my office is IP Telephony and not VOIP.

CCM 7.1 version installed on IBM server. If the CCM version is going to be 4.3, then it can be installed on Windows server. If its going to be 5.0 or above, then the CCM has to be installed on IBM/HP servers.

There are 5 servers out of which 3 are CCM servers configured in cluster. 1 for IPCC and other one of Unified Presence.

2 Gateways for PRI terminations. These gateways are 3845 router. These voice gateways are registered to CCM with CCM using MGCP.

For voice mail, we got OCS(Microsoft) integrated with CCM using SIP trunk. This is used as a replacement of Unity server.

PPPoE

sethuvignesh — Mon, 15 Nov 2010 11:50:44 +0000

PPPoE over Ethernet enhances PPPoE functionality by adding direct connection to actual Ethernet and FastEthernet interfaces. PPPoE over Ethernet provides service-provider digital subscriber line (DSL) support by enabling multiple hosts on a shared Ethernet interface to open PPP sessions to multiple destinations with one or more bridging modems.

ISPs often provide their customers with a DSL modem that has one Ethernet interface to connect to the customer Ethernet segment, and another interface for DSL line connectivity. In such a case, the DSL modem only acts as a bridge if the CPE is not configurable for any IP connectivity or enhanced features over DSL. This limits your connectivity to only one PPPoE Client PC. With the addition of a Cisco IOS router connected to the Ethernet of the DSL modem, you can run the PPPoE Client IOS feature on the Cisco router. This can connect multiple PCs on the Ethernet segment connected to the Cisco IOS router. With the use of the Cisco IOS router, you can enhance your DSL connectivities and all IOS features, such as Security, Network Address Translation (NAT) and Dynamic Host Configuration Protocol (DHCP) to internal hosts.

For the client:

1. under the ethernet interface, enable pppoe ‘pppoe-enable group ’

2. create a dialer interface, assign an IP, encap PPP, and associate the this interface to a dialer pool.

3. under the etheinterface, associate this interface to the dialer pool using the command, “pppoe-client dial-pool-number <>”

interface Ethernet0/0
no ip address
full-duplex
pppoe enable group CISCO
pppoe-client dial-pool-number 1

interface Dialer1
ip address 150.1.12.1 255.255.255.0
encapsulation ppp
dialer pool 1
end

For the server:

1. enable vpdn ‘vpdn enable’, create a vpdn-group ‘vpdn-group CISCO’, under the group ‘accept-dailin’ to make it a server.

2.Create a bba-group with the same name as vpdn group. Designate a virtual-template to that group.

3.configure the virtual-template with an IP.

4.under theethernet interface, enable pppoe.

vpdn enable
vpdn-group CISCO
accept-dialin

bba-group pppoe CISCO
virtual-template 1

interface Virtual-Template1
ip address 150.1.12.2 255.255.255.0

Doc CD: http://www.cisco.com/en/US/docs/ios/12_2/wan/configuration/guide/wcfppp.html#wp1076496

IPX Vol3 Lab2 learnings

sethuvignesh — Sun, 14 Nov 2010 08:09:56 +0000

Task 1.1:
Configure R2 Frame-Relay Interfaces so that IP traffic with a datagram size above 512 bytes will be marked Discard-Eligible (DE)?

A “frame relay de-list” and “frame-relay de-group” will allow matching of packet size and marking the traffic as discard-eligible. The DE-list is created in global config mode, and the DE group is configured on the interface, and bound to the DLCI.

Global config:
frame-relay de-list 1 protocol ip gt 512
On all subinterfaces:
frame-relay de-group 1

Task 2.2:
Configure ports FastEthernet0/19, FastEthernet0/20, FastEthernet0/21 and FastEthernet0/22 on both switches to automatically shut down if other switches are connected to them?

We can detect switches if they are configured for spanning-tree operation and are sending BPDUs. To accomplish automatic shutdown of the port when BPDUs are detected, we can use BPDU Guard feature.

int range fa0/19 -22
spanning-tree bpduguard enable

Task 3.2:
Configure the line so that if the link quality of the line drops below 80% it will shut down?

On both the directly connected interfaces configure “ppp quality 80″.

Task 3.3:
Use both serial links connecting R6 and R9 together to form a single bonded circuit. Configure with associated IP addressing as per Table A. Use Virtual-Template 1?

Serial links 0/2/0 and 0/2/1 connect R6 and R9. This connection can be configured using either dialer profiles or virtual templates. Create the virtual template first. Configure the virtual template with an IP address, encapsulation ppp and PPP multilink. Configure the global command multilink virtual-template to assign the virtual template to the multilink bundle. Configure the individual links for PPP encapsulation and for PPP Multilink.

multilink virtual-template 1 –>To specify a virtual template from which the specified Multilink PPP (MLP) bundle interface can clone its interface parameters
!
int virtual-template 1
encap ppp
ip address <> <>
ppp multilink
!
int s0/0/0
encap ppp
ppp multilink

Secure this link using a password of ipexpert. The password should not actually traverse the line?

Each side needs a username/password configured for the remote side,

username <> password <>
int s0/0
ppp authentication chap

Configure the MLPPP link to assure that if a single link is dropped, the entire interface goes down?

The command “ppp multilink links minimum” can specify the minimum number of links that we want to have. If both links are not available, the link should go down. Testing by shutting down the serial interface should shut down the virtual access as well,but it does not.

int virtual-template 1
ppp multilink links minimum 2

so In order to force the requirement of both links, the “mandatory” keyword may need to be used. After configuring this, the virtual-access interface is forced down.

int virtual-template 1
ppp multilink links minimum 2 mandatory

Task 4.1
The NET should be 49.0001.xxxx.xxxx.xxxx.00 where the system ID is the Loopback0 IP address (in hex)?

We are tasked with converting the IP addresses of the loopbacks to the ISIS system IDs. The system ID has a length of 12 hex characters for a total of 48 bits. The loopback IP addresses are 32 bits long, so we will prepend with zeroes.

First 16 bits – prepended zeroes – 0000.
Next 8 bits – first octet – 200 – converts to C8 hex. (You will have access to the Windows calculator in lab)
Next 8 bits – second octet – 0 – converts to 00 hex.
Next 8 bits – third octet – 0 – converts to 00 hex.
Last 8 bits – fourth octet – router number – value is same in hex since router numbers are less than 10.

R5 – system ID 0000.C800.0005
R6 – system ID 0000.C800.0006
R4 – system ID 0000.C800.0004
R2 – system ID 0000.C800.0002

Task 5.1:

Use new style BGP configuration. R4, R5 and R6 can only have one neighbor statement. Optimize R2s configuration for multiple BGP updates?

New style configuration requires configuring peers under the IPv4 address family. Due to
the way BGP updates are handled from peers within the same AS, you usually need to
have a full mesh. We can reduce the peerings necessary using a route-reflector. Since R4, R5, and R6 can only have one neighbor, we will configure R2 as a route-reflector. In order to optimize R2 for updates, we can configure R2 for a peer-group. The peer-group is useful when you have multiple peers that have the same outbound policy. Rather than
processing the outbound update for each peer, the router will process the update once and send multiple copies.

On RR:
router bgp <>
nieghbor peer-group
nieghbor remote-as <>
nieghbor update-source lo0
nieghbor peer-group
address-family ipv4
neighbor route-reflector client

On Client:
router bgp <>
neighbor remote-as <>
neighbor update-source lo0
address-family ipv4
neighbor activate

INE Vol1 MPLS QoS

sethuvignesh — Fri, 29 Oct 2010 15:01:05 +0000

1. The qos group inbound does nothing and is not required. Use these outbound on PE-CE links if wanted to use SP markings.

policy-map FROM_CE
class VOIP
set qos-group 5 —-> not needed
set mpls experimental imposition 5
class class-default
set qos-group 1—–> not needed
set mpls experimental imposition 1

2. The qos configuration outbound on frame-relay interface Serial 0/0 on R2 does not function when a UDP traffic is originated from SW1-SW2. The service-policy output TO_CE on R4 does not match anything on the 2 classes(MPLS_EXP5 and MPLS_EXP1) but only on class-default.
The only way I managed to make it work was to use frame-relay map-class and activate it on each subinterface on R2 and R4.

R2:

map-class frame-relay FRTS
frame-relay cir 45000000
frame-relay bc 4500
frame-relay be 0
service-policy output TO_PE

interface Serial2/0
frame-relay traffic-shaping
int s2/0.1
frame-relay interface-dlci 204
class FRTS

R4:

map-class frame-relay FRTS
frame-relay cir 45000000
frame-relay bc 4500
frame-relay be 0
service-policy output From_P

int s1/0
frame-relay traffic-shaping
int s1/0.1
frame-relay interface-dlci 402
class FRTS

3. Also you have to enable FRTS to get CBWFQ working on 7200.

Good Links for MPLS QoS

sethuvignesh — Fri, 29 Oct 2010 14:07:25 +0000

http://www.cisco.com/en/US/docs/ios/12_2t/12_2t13/feature/guide/ftdtmode.html

http://www.ciscointernethome.org/en/US/technologies/tk543/tk759/technologies_white_paper0900aecd80295abb.pdf

http://cisco.com/en/US/products/ps6615/products_white_paper09186a00800a4455.shtml

Use of MPLS QoS for Ethernet over MPLS

sethuvignesh — Thu, 28 Oct 2010 13:30:47 +0000

Normally the packet for which the QoS was set was an IP packet or a labeled packet.
However, in the case of Ethernet over MPLS (EoMPLS), the forwarded packet is actually an Ethernet frame. If the frame is a non-VLAN Ethernet frame, it does not have QoS information embedded. If the frame is an 802.1Q frame, though, the Priority bits (P bits) in the 802.1Q header designate a QoS value. If a service provider carries the 802.1Q Ethernet frames over an MPLS network as in the case of point-to-point EoMPLS or VPLS, it would be nice if he could police the traffic and recolor it, if needed. You can do this in Cisco IOS. You can match the 802.1Q Priority bits in MQC by matching cos values in the class map.

In this below configuration the EXP bits are set to 1 on the tunnel and VC label on the ingress PE, if the 802.1Q P bits are 1, 2, or 3.

interface e0/0
service-policy input foo
!
class-map match-all foo-class
match cos 1 2 3
!
policy-map foo
class foo-class
set mpls experimental 1

MPLS DiffServ Pipe Model using discard class

sethuvignesh — Wed, 27 Oct 2010 10:39:27 +0000

In this configuration, the experimental bits 0 and 1 are mapped into qos-group 1, but with a different discard-class, discard-class 1 and 2, respectively. The different discard-class provides a different drop precedence. The experimental bits 2 and 3 are mapped to qos-group 2, with discard-class 1 and 2, respectively. On the egress interface, the packets from one qos-group go into one queue, but in that queue are packets that have two different drop precedence levels.

!Ingress interface:
class-map MPLS-AF11
match mpls experimental topmost 0
!
class-map MPLS-AF12
match mpls experimental topmost 1
!
class-map MPLS-AF21
match mpls experimental topmost 2
!
class-map MPLS-AF22
match mpls experimental topmost 3
!
policy-map set-MPLS-PHB
class MPLS-AF11
set qos-group 1
set discard-class 1
class MPLS-AF12
set qos-group 1
set discard-class 2
class MPLS-AF21
!
set qos-group 2
set discard-class 1
class MPLS-AF22
set qos-group 2
set discard-class 2
!
interface ethernet 3/0
service-policy input set-MPLS-PHB

!Egress interface:
class-map IP-AF1
match qos-group 1
!
class-map IP-AF2
match qos-group 2
!
policy-map output-qos
class IP-AF1
bandwidth percent 20
random-detect discard-class-based
class IP-AF2
bandwidth percent 30
random-detect discard-class-based
!
interface ethernet 3/1
service-policy output output-qos

Implement the MPLS DiffServ Short Pipe model in Cisco IOS

sethuvignesh — Wed, 27 Oct 2010 10:20:03 +0000

Only the configuration of egress PE is shown, because this LSR has a different configuration from the previous example. Namely, the egress LSR forwards the packet based on the precedence or DSCP bits of the IP packet after removing the labels. The egress LSR does not copy the EXP bits to the precedence bits of the outgoing IP packet.

Egress PE: MPLS DiffServ Short Pipe Model

!Egress Interface:
class-map IP-AF1
match ip precedence 2 4
!
policy-map output-qos
class IP-AF1
bandwidth percent 40
random-detect precedence-based
!
interface ethernet 3/0
service-policy output output-qos