Network technologies and trends


January 24, 2011  4:51 AM

Cisco Systems has announced the availability of Beta CCIE Service Provider v3.0 written Exam

Yasir Irfan Yasir Irfan Profile: Yasir Irfan

According to Cisco Learning Network the beta version of the CCIE Service Provider Written Exam v3.0 (351-029) will be available for scheduling and testing at all worldwide Cisco-authorized Pearson VUE testing centers. This opportunity is valid from February 18, 2011 and continuing through March 18, 2011.  One great news about the CCIE Service Provider Written Exam v3.0 (351-029) is you can schedule and write the exam on same day. Also all beta exam takers are eligible to take the CCIE Service Provider Written Exam v3.0 (351-029) at a discounted price of 50 USD with full recertification or lab qualification credit granted to all passing candidates.  Candidates preparing for this exam should refer to CCIE Service Provider v3.0 Exam Topics on the Cisco Learning Network for a detailed outline of the topics covered.

You can expect the beat exam results in six to eight weeks after the close of the beta period. Therefore, CCIEs in suspended status with an expiration date before May 31, 2011 should recertify using another exam.  Candidates may only attempt a beta exam once during the beta period.

January 22, 2011  12:42 PM

Trunking encapsulation mismatch was the problem

Yasir Irfan Yasir Irfan Profile: Yasir Irfan

“Jan 22 09:09:33: %EC-SP-5-CANNOT_BUNDLE2: Te1/7 is not compatible with Te2/7 and will be suspended (trunk mode of Te1/7 is dynamic, Te2/7 is trunk)”

If you see the above error especially while creating a port-channel between Cisco 6500 Series and Cisco 3750 E Series switches don’t panic. You will see the error when there is a trunking encapsulation mismatch for the interfaces associated with the port-channel. When we changed the trunk settings in the both interfaces the problem was solved and port-channel was established.

When the following error occurred

“Jan 22 09:09:33: %EC-SP-5-CANNOT_BUNDLE2: Te1/7 is not compatible with Te2/7 and will be suspended (trunk mode of Te1/7 is dynamic, Te2/7 is trunk)”

The tenGigabitEthernet 1/7 was configured with switchport trunk encapsulation dot1q. When we removed the command with “no switchport trunk encapsulation dot1q” the problem was solved.

Basically the issue was one link was configured for dynamic trunking and other was a trunk a port without any negotiation enabled.


January 18, 2011  11:39 AM

What are Private VLANs (PVLANS)?

Yasir Irfan Yasir Irfan Profile: Yasir Irfan

If you are working hard towards achieving Cisco CCNP Switch 642-813 certification exams, private VLANs does comes into picture. Yeah its part of CCNP Switch 642-813 curriculum.  Cisco basically designed Private VLANs (PVLANS) as part of layer 2 security, in normal condition in any given network the traffic is allowed to move unconditionally within a VLAN. What if you want to restrict the movement of traffic with in a VLAN?  Private VLAN (PVLANS) comes into picture.

Private VLAN (PVLANS) are really just sub-VLAN inside a VLAN, they basically allows you to split the VLAN domain into multiple isolated subdomains. When it comes to inter-VLAN routing we need a Layer 3 device to forward packets. The same analogy applies to Private VLAN (PVLANS). They need layer 3 devices such as Cisco Router or Cisco Multilayer Switch.

To make things much simpler, consider a Network environment in which the service provider need to connects servers belonging to different customers to the Internet. These servers must all be able to reach their first-hop router, but for security reasons, servers belonging to one customer must not be able to communicate with servers belonging to another. An obvious design solution for these requirements is to place each customer’s servers in a separate VLAN, which also requires the assignment of a separate IP subnet per customer (even if they have only one server).

By creating separate VLANs not only wastes the VLAN IDs but also IP addresses as well. To overcome this Private VLAN (PVLANS) were introduced as a more elegant alternative, allowing multiple devices to reside in the same IP subnet, yet remain isolated from one another at layer two.

In upcoming post we see what terminologies are used in Private VLAN (PVANS) and how they are distinguished.


January 6, 2011  9:07 PM

Mac OS X 10.6.6 Released with Mac App Store

Yasir Irfan Yasir Irfan Profile: Yasir Irfan

Apple has just released Mac OS X 10.6.6 Snow Leopard update. The update brings support for Apple’s Mac App Store, which is launching today. It is a recommended update and it implements hundreds of fixes since the last few updates. The store will allow customers to find and install apps the same way they do with iOS apps. You can get the update from Snow Leopard’s Software Update, or directly from the Software Downloads page here.

Currently I am downloading the update and let me see what Apple’s Mac App Store is going to offer?


January 5, 2011  6:05 AM

What happened to “write memory” IOS command in Cisco Nexus 7000 Series Switch?

Yasir Irfan Yasir Irfan Profile: Yasir Irfan

When configuring Cisco Catalyst Switches, I quite often use “write memory” command to save my configuration rather than using “copy running-configuration startup-configuration” Cisco IOS command. Other day I was saving my running configuration to the startup configuration in a Cisco Nexus 7000 Series Switch in the usual way ” wri mem”. But I got the following error

VDC-Admin-DC-AGG1# write memory
^
% Invalid command at ‘^’ marker.
VDC-Admin-DC-AGG1#


Now Cisco Nexus 7000 Series switch won’t support the “write memory” command. Rather you need to use the “copy running-configuration startup-configuration” to save your configuration. One more difference I figured out between Cisco IOS and NX-OS is the missing of “write memory” command.

VDC-Admin-DC-AGG1#
VDC-Admin-DC-AGG1# write ?
erase  Destroys the configuration on persistent media

VDC-Admin-DC-AGG1# write

Now the time has come for me better start using “copy running-configuration startup-configuration” command in NX-OS based Cisco switches.


December 30, 2010  8:38 PM

What are key features and benefits NX-OS offers Series 2

Yasir Irfan Yasir Irfan Profile: Yasir Irfan

In my previous post I did discussed about some of the key features of NX-OS lets see what else it offer

  • Base services: The default license that ships with NX-OS covers Layer 2 protocols including such features such as Spanning Tree, virtual LANs (VLAN), Private VLANS, and Unidirectional Link Detection (UDLD).
  • Enterprise Services Package: Provides Layer 3 protocols such as Open Shortest Path First (OSPF), Border Gateway Protocol (BGP), Intermediate System-to-Intermediate System (ISIS), Enhanced Interior Gateway Routing Protocol (EIGRP), Policy-Based Routing (PBR), Protocol Independent Multicast (PIM), and Generic Routing Encapsulation (GRE).
  • Advanced Services Package: Provides Virtual Device Contexts (VDC), Cisco Trustsec (CTS), and Overlay Transport Virtualization (OTV).
  • Transport Services License: Provides Overlay Transport Virtualization (OTV) and Multiprotocol Label Switching (MPLS) (when available).


December 30, 2010  8:35 PM

What are key features and benefits NX-OS offers Series 1

Yasir Irfan Yasir Irfan Profile: Yasir Irfan

Apparently the NX-OS includes some quite interesting kef features and benefit. In this post I will try to highlight few of those features. Some of them are as follows

  • Virtual device contexts (VDC): Cisco Nexus 7000 Series switches can be segmented into virtual devices based on customer requirements. VDCs offer several benefits such as fault isolation, administration plane, separation of data traffic, and enhanced security.
  • Virtual Port Channels (vPC): Enables a server or switch to use an EtherChannel across two upstream switches without an STP-blocked port to enable use of all available uplink bandwidth.
  • Continuous system operation: Maintenance, upgrades, and software certification can be performed without service interruptions due to the modular nature of NX-OS and features such as In-Service Software Upgrade (ISSU) and the capability for processes to restart dynamically.
  • Security: Cisco NX-OS provides outstanding data confidentiality and integrity, supporting standard IEEE 802.1AE link-layer cryptography with 128-bit Advanced Encryption Standard (AES) cryptography. In addition to CTS, there are many additional security features such as access control lists (ACL) and port-security, for example.


December 30, 2010  8:31 PM

A brief overview of Cisco NX-OS

Yasir Irfan Yasir Irfan Profile: Yasir Irfan

No doubt Cisco Nexus 7000 Series switch is a better choose for Data Center so does the NX-OS. Cisco Systems built the NX-OS data center-class operating system with modularity, resiliency and serviceability as it foundation. Cisco Systems designed NX-OS based on Cisco Storage Area Network Operating System (SAN-OS) software. Some of the advantages of Cisco NX-OS are as following

  • Unified data center operating system
  • Robust and rich feature set with a variety of Cisco innovations
  • Flexibility and scalability
  • Modularity
  • Virtualization
  • Resiliency
  • IPv4 and IPv6 IP routing and multicast features
  • Comprehensive security, availability, serviceability, and management features


December 30, 2010  1:21 PM

Skype outage was caused by a bug in its client

Yasir Irfan Yasir Irfan Profile: Yasir Irfan

In his blog post Lars Rabbe , Skype’s chief Information officer revealed that the recent Skype outage was caused by the peer-to-peer (P2P) network becoming unstable and suffering a critical failure.

The failure lasted approximately 24 hours from December 22, 0800 PST/1600 GMT to December 23, 0800 PST/1600 GMT.

According to Lars their support servers responsible for offline instant messaging became overloaded. Which resulted in delayed responses to some of Skype clients. The Skype for Windows client (version 5.0.0152) crashed dye to delayed responses from overloaded severs.

His detailed explanation can be accessed from his blog post.


December 30, 2010  1:06 PM

According to Shaw Wu,BlackBerry PlayBook launch may delay due to battery issues

Yasir Irfan Yasir Irfan Profile: Yasir Irfan

According to Kaufman Brothers analyst Shaw Wu, BlackBerry’s answer to iPad and Samsung Galaxy Tab, BlackBerry Playbook needs a re-engineering to improve its battery life. The Playbook is due to be released in 2011.

“Wu claims he is hearing that the PlayBook “needs to improve its relatively poor battery life of a few hours compared to 6 hours for the Samsung Galaxy Tab and 10 hours for [Apple’s] iPad.” As a result, Wu writes, the launch of the BlackBerry PlayBook may be delayed until May, 2011. Wu notes that the cause of the battery issues may stem from the fact that QNX, the PlayBook’s operating system, was designed for use in scenarios where battery life is not an issue — such as in automobiles.”

Wu has also raised concerns over app store monetization. Apple is the only store where developers can count on revenue, while Android “suffers from piracy and inconsistency”.

Wu has estimated that RIM will ship around 700,000 PlayBooks next year, while other analysts have predicted up to one million shipments.

RIM has announced that the PlayBook measures 5.1 inches by 7.6 inches by 0.4 inches and weighs 0.9 pounds. The PalyBook has a 1024-by-600 multitouch capacitive display, designed around a dual-core, 1-GHz Cortex A9 microprocessor with one gigabyte of RAM.

The tablet will run QNX’s mobile operating system, as well as HTML5 and Flash 10.1, with native hardware support to accelerate apps further.


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