Category: Networking

I stepped on this issue few weeks ago. I was implementing a new ASA Firewall solution, first time for me with software newer than version 8.4.2

It seems that all those stories about changes in the NAT logic after that version were true. This is what I found out about ASA packet processing.

Configuration was really straightforward and everything worked fine except one thing. When connected remotely using Cisco AnyConnect I was able to access all devices inside the network (inside ASA firewall), but not the ASA itself. I wasn’t able to connect with SSH nor with ASDM.

Quantum cryptography is a new technique of securing computer network communication channel. Existing standard crypto systems are using advanced algorithms to create key pairs which are extremely hard to inverse engineer. Quantum cryptography avoids any mathematical algorithm and uses principles of quantum physics.

Quantum crypto implements a new technique of generating and exchanging crypto keys which makes it impossible for third party entities to get those keys by snooping or to create man in the middle by snooping and sending copies of original key. Keys generated in this way will automatically destroy themselves if read by third-party interferer.

When generated between two sides, using quantum key distribution, secret keys will be used with standard and well known symmetric encryption. The key generation process is the only part which uses quantum principles to work, from there, using this “hyper-secure key” already existing symmetric encryption will be used to encrypt and decrypt data, which will be sent over standard, currently available, optic data networks.

If you want to send or store data and be sure it is safe from being intercepted, you will use Cryptography. Cryptography uses chipper as mathematical virtual lock to make data scrambled so that is not understandable if intercepted by unauthorized third parties.

There are different cryptography techniques, some of them are: encryption, hashing, and steganography.

Cryptography can be differentiated by usage of different key types:

• Symmetric Key Encryption
• Asymmetric Key Encryption

Symmetric Key Encryption is sometimes known as Secret Key Cryptography. Main characteristic of this type of cryptography is the same key usage in encryption and decryption of transferred data. Every change in the secret key will make data decryption impossible.

Asymmetric Key Encryption is known as Public Key Cryptography technique. Main characteristic of this type of cryptography is usage of two sets of keys which are generated for the process. One key is public and other is private. Public key encrypts the data. We can only decrypt that data using appropriate private key. The best part of asymmetric cryptography is that is giving us a technique to share encrypted data and enable the receiver to decrypt that data without sending the decryption key across unsecured network.

For a shorter update procedure guide check abbreviated article: Short list of upgrade steps without extensive explanations “Cisco Catalyst 6880-X VSS ISSU Upgrade Steps“

Intro

Cisco spoiled us over the years with great and detailed documentation on each technology and hardware component they support. Still, I managed to find a part where documentation is not detailed enough to give you definite number of steps to get things done.

While preparing for software upgrade of Cisco Catalyst 6880-X VSS cluster I stumbled on one of the first examples of outdated and vague procedure for upgrade of Cisco device. Here is my successful ISSU (In-Service Software Upgrade) procedure which I done few days ago. I hope it will help you avoid sweating and hoping that you typed the right thing on a VSS cluster that should not go down at any point 🙂

I included an Acronym Guide at the bottom of the post to guide you trough VSS, ISSU, Cluster, and other mentioned abbreviation which are not described in details here

In my case the environment was Catalyst 6880-X and four 6800ia Fabric Extenders FEX. The same procedure is valid for more on for no FEX extenders.

Cisco Catalyst 6880-X VSS

Get the info on which IOS version is supported to be upgraded with ISSU

Not all IOS images can be upgraded to new IOS versions using In Service procedure to avoid network traffic downtime. In order to get things working, you need to get into Cisco docs and find ISSU supported upgrade matrix document.

This is a short version without comments and explanations for those that need to get things done quickly without reading through my extensive waffle.

For detailed update procedure with all the explanations check extended article: “ISSU Upgrade of Cisco Catalyst 6880-X VSS cluster and its four 6800ia FEX extenders“

Let’s start!

1. Get the info on which IOS version is supported to be upgraded with ISSU

Google for ISSU or EFSU IOS upgrade support or use this Cisco doc “SX_SY_EFSU_Compatibility_Matrix1” to select supported IOS for ISSU upgrade from your current version.

2. Upload IOS to both Chassis

copy ftp://admin:[email protected]/c6880x-adventerprisek9-mz.SPA.151-2.SY7.bin bootdisk:

and same for slavebootdisk: