Cisco UCM CAR (CDR) Web GUI Access Request (https:///car/)

http://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/admin/11_5_1_SU1/Administration/cucm_b_administration-guide-1151su1/cucm_b_administration-guide-1151su1_chapter_010.pdf

 

To provide a user to CAR (CDR)  (https://<CAR server IP Address>/car/) web page, the following two access groups must be associated with the user. After giving user this access, please test login to other areas of UCM GUI, so the users do not gain unapproved access to UCM Admin pages.

 

  1. Standard CCM End Users
  2. Standard Admin Rep Tool Admin = (Standard CAR Admin Users, Standard CCM Super Users)

 

CAR web gui

Interview question: Cisco Voice Engineer: CUCM Database replication value, do you know what you are talking about?

This is a helpful reminder note for all who manages CUCM on day-to-day basis and one of the favorite Voice/IPTel Engineer interview questions. I think I was asked this question in almost every voice Engineer role interviews. Good luck with your next interview!

Q1. What does CUCM database replication value mean to you (CM Administrator)? 

2 = Good, excellent, no behind pain

Other than 2 = Behind pain begins

Value Meaning Description
0 Initialization State This state indicates that replication is in the process of trying to  setup. Being in this state for a period longer than an hour could  indicate a failure in setup.
1 Number of Replicates not correct This state is rarely seen in 6.x and 7.x but in 5.x can indicate its  still in the setup process. Being in this state for a period longer than  an hour could indicate a failure in setup.
2 Replication is good Logical connections have been established and tables match the other servers on the cluster.
3 Tables are suspect Logical connections have been established but we are unsure if tables match.
In 6.x and 7.x all servers could show state 3 if one server is down in  the cluster.
This can happen because the other servers are unsure if  there is an update to a user facing feature that has not been passed  from that sub to the other device in the cluster.
4 Setup Failed / Dropped The server no longer has an active logical connection to receive  database table across. No replication is occurring in this state.

Source: CCO

Q2. How to check?

Option 1: On CUCM OS CLI, run show command

admin:show perf query class “Number of Replicates Created and State of Replication”
==>query class :

– Perf class (Number of Replicates Created and State of Replication) has instances and values:
ReplicateCount -> Number of Replicates Created = 427
ReplicateCount -> Replicate_State = 2 <<< Life is Good

Option 2: On CUCM Unified Reporting 

Cisco Unified Reporting > System Reports > Unified CM Database Status >> Run report

 

%ec%82%ac%ec%9a%a9%ec%9e%90-%ec%a7%80%ec%a0%95-12%ec%82%ac%ec%9a%a9%ec%9e%90-%ec%a7%80%ec%a0%95-13

Option 3: Real Time Monitoring Tool (RTMT)

Install RTMT plugin on your desktop. Launch RTMT and then go to “Call Manager > Service > Database Summary”

Q3. How to repair a broken db replication issue?

I have come acorss a very good blog and it shows you on how to repair a broken db replication. Click here.

 

 

 

Notes on Cisco QoS: Clearing the fog – Part 2. Quality issues

Quality of Service

QOS = Method of giving priority to some specific traffic as moving over the network.

The basic aim of QoS is to have a consistent and predictable performance on your network.

 

1 qos intro

General characteristics of today’s Converged Network:

  • Small voice packet compete with bursty data packets, many different applications are using network as services
  • Critical traffic must get priority over less critical traffic, without QoS, default behavior is First In First Out (FIFO)
  • Voice and video traffics are time-sensitive
  • Outages are not acceptable

 

Converged Network Quality issues:

  • Lack of Bandwidth
  • Packet Loss
  • Delay
  • Jitter

 

Bandwidth

2 Bandwidth Measure.png

  • Maximum available bandwidth is the slowest link on the traffic paths
  • On the same physical links (traffic paths), multiple flows compete for the same bandwidth, multiple applications sharing the same bandwidth
  • Lack of bandwidth causes performance degradation on network applications

 

 

Packet Loss

3 Tail Drop due to Queue Congestion

Packet loss due to Tail Drop: Queue only can so much packets and once it is full and more packets arrive at the tail end of the queue before the queue is emptied (due to link congestion etc.), the packets will be dropped, and this behavior is called ‘Tail Drop’. If the tail drop occurs to the time sensitive traffics such as voice and video, the effects are immediately felt by the users on the flow. If this happens to data traffic, it may interrupt file transfer and corrupt the file.

 

 

Delay

4 Types of Delay

  • Processing Delay – time taken by router to process packets from an input interface and put them into the output queue of output interface
  • Queuing Delay – time a packet resides in the output queue of a router
  • Serialization Delay – time taken to place bits on the wire
  • Propagation Delay – time taken for packets to cross links from one end to the other end

 

 

Jitter

5 Jitter

  • Packets from a source will reach a destination with different delay times
  • Congestion on the network will cause jitter
  • Congestion can occur at a router interface/Service Provider network if the circuits are not properly provisioned

 

CCNA Data Center 640-911 DCICN – Note 18, IPv6 Introduction

This is my first blog in 2016, I have been on holiday mode as I have been on one the longest annual leave in my life. Hope you understand the family commitment when you and your kids are on summer holiday (here in Sydney, Dec/Jan/Feb is blazing summer).

 

IPv6, the history and does it really matter to you or anyone?

The simple answer is YES, then why? The single biggest driver behind the development and introduction of IPv6 is  a long prediction of lack of usable IPv4 IP addresses since the explosion of World Wide Web (www) in 1995. The www development goes back to 1991 and then the introduction of grandfather web browser, Mosaic was first introduced in 1993. By year 1995, one third of IPv4 addresses were consumed, by year 2000, half of all IPv4 addresses were use.

As reviewed in previous notes, IPv4 consists of 32 bit address structure and theoretically that should give us 2 to the power of 32 IP addresses, that is 4294967296 IP addresses or roughly, 4.3 billion IP addresses . But not all IP addresses are usable such as the reserved IP addresses for private network use as well as the Class E addresses reserved for development and testing purposes. In other words, only around 2.5 billion IP addresses are true usable addresses. If you just check out our world’s population today ( http://www.worldometers.info/world-population/, China = 1.407 billion and India = 1.2912 billion people,), just looking at top two countries’ population figures, you can feel the IPv4 address shortage on your skin. The trend is that the world’s network has been doubling in size every year for the past 15 years. (https://en.wikipedia.org/wiki/IPv4_address_exhaustion)

With the advancement of new technologies comes the rapid deletion of available IPv4 IP addresses. Anything that’s related to mobile communications and entertainment as well as all other areas seems to be needing more and more IP addresses for everyday use. In the past, it was expected that all the IPv4 addresses would be depleted by 2011 but it is 2016 and we are still using IPv4 address without much thought, all thanks to the counter measures put into place to slow down the IPv4 IP address deletion. e.g.) The fine art of sub-netting, a practical use of DHCP and IP Natting.

 

 Quick note on history of IPv6:

1990 – IETF had predicted that all class B IPv4 IP addresses will be deleted by 1994
1991 Nov – IETF formed  ROAD (ROuting and ADress) Group in Santa Fe, US.
1995 – IPNG (IP Next Generation) Workgroup had written and submitted ‘RFC 1883’, this RFC has become the foundation of current IPv6.
1996 – 6Bone was introduced. 6Bone was a test-bed for IPv6 vulnerabilities connecting 57 countries across 1100 sites.
1999 – IPv6 Forum was launched to standardize the use of IPv6
2006 Jul 06 – 6Bone was decommissioned after 10 years of testing.
Current – Majority of IP products are manufactured with IPv6 capabilities and compatibility. IPv6 is slowly phasing out IPv4 around the world.

Source: https://en.wikipedia.org/wiki/IPv6

 

Quick note on 10 Advantages (Characteristics) of IPv6:
1. Larger IP address space than IPv4, 32 bits based IPv4 vs 128 bits based IPv6
2. Better end-to-end connectivity than IPv4
– peer-to-peer application connections such as games, video conferencing, file sharing and VoIP
– No need to use NAT as the shortage of addresses is thing of IPv4
3. Plug-n-Play feature of IPv6
– plug-and-play auto-configuration, e.g.) DHCPv6
4. Simplified Header structures leading to faster routing
5. Better security features
– use of IPSec (a built-in feature)
6. Improved QoS features
7. Improved Multicast and Anycast abilities
8. Better mobility features
9. Ease of administration over IPv4
10. IPv6 follows the key design principles of IPv4

Source: http://www.ipv6.com/articles/general/Top-10-Features-that-make-IPv6-greater-than-IPv4.htm

In the next section, we will look at some characteristics of IPv6 and then in the final section of IPv6, I will demonstrate IPv6 in a simple lab. Happy blogging, reading and all the best with your learning and career in 2016.

Notes on Cisco QoS: Clearing the fog – Part 1. Basic Introduction

  1. What is Quality of Service (QoS) ?

Analogy 1: QoS is a network tool which can be implemented to effectively transport more critical traffics over IP, which gives critical traffic a priority over less critical traffic.

Analogy 2: QoS is a method of giving a priority to some specific data traffic going across our network.

  • Give VoIP, Video traffic more priority than ftp file downloading traffic
  • Some critical Data such as Citrix etc.

 

  1. Converged Network Quality Issues

Today’s enterprise network Characteristics:

  • Benign small voice packet flows compete directly with busty data packet flows.
  • Voice load and voice application data (traffic) tolerate minimal variation in delay, packet loss or jitter. The voice quality degradation is immediately felt by the users.
  • Give critical traffic higher priority
  • Voice and video are real-time, hence time-sensitive
  • Outage/packet drops are not acceptable

 

Some issues from Converged Network:

  • Lack of bandwidth – If more traffic is pumped through the network more than the network can handle, there will be congestions and packet loss.
  • Packet Loss – If input queue pumps too much packets into an interface, output queue fills up, the packet is dropped.
  • Delay –
    • Processing delay – The time it takes for a router to take the packet from an input interface, examine it and put it into the output queue of the output interface
    • Queuing delay – The time a packet resides in the output queue of a router
    • Serialization delay – The time it takes to place the “bits on the wire”
    • Propagation delay – The time it takes for the packet to cross the link from one end to the other

 

  • Jitter –
    • Packets from the source will reach the destination with different delays
    • Jitter is generally caused by congestion in the IP network
    • The congestion can occur either at the router interfaces or in a provider or carrier network if the circuit has not been provisioned properly

 

To overcome these converged network quality issues, QoS tool(s) must be used based on each network.

 

Some Cisco recommended QoS tool types and their characteristics:

A. Best effort

– Out of box, if you do not configure your devices, it is using best effort

– Business network with no QoS policies

– Infrastructure does not support QoS

– FIFO

 

B. Integrated Services (IntServ)

– Aims to reserve bandwidth along a specific path in the network

– Guarantees end-to-end bandwidth for mission-critical applications such as VoIP and Citrix

– End-hosts signal their QoS requirements to the network (Signalled QoS model)

– Every communication stream needs to request resources from the network.

– Edge routers use Resource Reservation Protocol (RSVP) to signal and reserve bandwidth

 

Some disadvantages of IntServ:

– Every device along the network must be fully RSVP aware and have ability to process QoS

– Reservations in each devices along the path need to be periodically refreshed, adds traffic and overhead along the network

– “Soft-states” or bandwidth reservation increase memory and CPU requirements on devices along the path

– Adds complexity to the network which makes network infrastructure difficult to maintain

 

C. Differentiated Service (DiffServ)

– Designed to overcome the limitations of Best-Effort and IntServe model, while maintaining the ability to provide an almost guaranteed QoS

– Routers and switches are configured to service multiple classes of traffic with different priorities. Bandwidth, delay and prioritization are configured on a hop-to-hop basis along the network infrastructure, making diffServ cost-effective and scalable

– For DiffServ QoS to work, network traffic must be divided into classes that are based on the company’s requirements

– Network devices identify traffic as it passes through them and enforce the configured policies, making sure that each class/service is served as instructed

 

Reference:

http://docwiki.cisco.com/wiki/Quality_of_Service_Networking

http://searchunifiedcommunications.techtarget.com/tip/DiffServ-QoS-model-works-wonders-for-VoIP-networks