Network technologies and trends


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.


December 29, 2010  5:27 AM

How to allocate physical interfaces to VDC in a Cisco Nexus 7000 Series switch?

Yasir Irfan Yasir Irfan Profile: Yasir Irfan

 

To allocate physical interfaces to VDC from the config terminal mode type the VDC name and then allocate the physical interfaces as shown below by using the command “allocate interface”

N7000-ITKE01#configure t

N7000-ITKE01 (config)#vdc VDC-CORE1

N7000-ITKE01-DC-CORE1 (config-vdc)#allocate interface  Ethernet1/1

N7000-ITKE01-DC-CORE1 (config-vdc)#allocate interface  Ethernet1/2

N7000-ITKE01 -DC-CORE1 (config-vdc)#allocate interface  Ethernet1/3

Now let’s verify the Interface allocation to the VDC by using following command ” show vdc membership”

N7000-ITKE01-DC-CORE1# show vdc membership

vdc_id:2 vdc_name: DC-CORE1 interfaces:
        Ethernet1/1           Ethernet1/2           Ethernet1/3          
        Ethernet1/4           Ethernet1/5           Ethernet1/6          
        Ethernet1/7           Ethernet1/8           Ethernet1/9          
        Ethernet1/10          Ethernet1/11          Ethernet1/12         
        Ethernet1/13          Ethernet1/14          Ethernet1/15         
        Ethernet1/16          Ethernet1/17          Ethernet1/18         
        Ethernet1/19          Ethernet1/20          Ethernet1/21         
        Ethernet1/22          Ethernet1/23          Ethernet1/24         
        Ethernet1/25          Ethernet1/27          Ethernet1/29         
        Ethernet1/31         

N7000-ITKE01-DC-CORE1#

In addition to interfaces other physical resources such as IPv4 router memory, IPv6 router memory, port-channels, SPAN sessions can be allocated to individual VDC.


December 28, 2010  5:44 AM

How to configure VDC in Cisco Nexus 7000 Series switch?

Yasir Irfan Yasir Irfan Profile: Yasir Irfan

In my previous post we came to know briefly about Virtual Device Contexts (VDC) and what are the advantages of Virtual Device Contexts (VDC) as well.

Configuring Virtual Device Contexts (VDC)   Cisco Nexus 7000 Series switch is as simple as just entering the VDC name, by following below mentioned steps we can create VDC named VDC-Admin

Step 1

Connect to Cisco Nexus 7000 Series switch using a console port.

Step 2

Create a VDC named DC-CORE1

N7000-ITKE01#configure t

N7000-ITKE01 (config)#vdc  DC-CORE1

Step 3

Verify the created VDC by using following commands “Show vdc” and “show vdc VDC-CORE1 detail” as demonstrated below.

N7000-ITKE01# sho vdc

vdc_id  vdc_name                          state               mac            
——  ——–                          —–               ———-     
1       VDC-Admin                         active              00:26:98:07:1c:c1
2       DC-CORE1                          active              00:26:98:07:1c:c2
3       DC-AGG1                           active              00:26:98:07:1c:c3

 

The show VDC command shows VDC id based on which VDC created first.BY default VDC id is assigned to the default VDC. In this case it is VDC-Admin.

VDC-Admin# sho vdc DC-CORE1 ?
  <CR>       
  >           Redirect it to a file
  >>          Redirect it to a file in append mode
  detail      Show detailed vdc information
  membership  Show vdc interface membership information
  resource    Show resource configuration for VDC
  |           Pipe command output to filter

N7000-ITKE01# sho vdc DC-CORE1 detail

vdc id: 2

vdc name: DC-CORE1
vdc state: active
vdc mac address: 00:26:98:07:1c:c2
vdc ha policy: RESTART
vdc dual-sup ha policy: SWITCHOVER
vdc boot Order: 1
vdc create time: Wed Dec 28 08:44:51 2010
vdc reload count: 0
vdc restart count: 0

N7000-ITKE01#

 

 

 

 

In upcoming post I will show how to allocate physical interfaces to the newly created VDC.


December 27, 2010  6:22 AM

What is Virtual Device Contexts (VDC) in Nexus 7000 Series Switches?

Yasir Irfan Yasir Irfan Profile: Yasir Irfan

 

The Virtual Device Contexts (VDC) is a new feature introduced in Cisco Nexus 7000 NX-OS, so does it happens to be the first Data Center Switch to provide Virtual Device Contexts (VDC) capabilities. The Virtual Device Contexts (VDC) allows a Cisco Nexus 7000 Series switch to be logically segmented into four different virtual switches (device contexts). The logical separation of single Nexus 7000 into multiple logical devices provides the following benefits:

  • Administration and management separation
  • Change and failure domain isolation from other VDSs
  • Address, VLAN, VRP and vPC isolation.

When the Cisco Nexus 7000 Series switch is first booted, all interfaces of all line cards in the modular switch platform are placed in the default VDC (VDC 1).  Up to four VDCs can be created including the default VDC, but an interface can only belong to one VDC.  Interfaces from different line cards can be placed in different VDCs.  Once an interface is placed into a VDC, the interface can no longer be managed in the default VDC context.

The Cisco Nexus 7000 Series switch shares some components between VDC(s), which include the following:

  • A single instance of the kernel which support all of the processes and VDCs.
  • Supervisor Modules
  • Fabric Modules
  • Power Supplies
  • Fan trays
  • System fan trays
  • CMP
  • CoPP
  • Hardware SPAN resources.


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