Tag: configuration

Cisco Catalyst 6880-X VSS ISSU Upgrade Steps

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:

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Juniper vMX Multicast Configuration

I’m fairly new to Juniper CLI. For one of my first tries, I decided to make my life difficult by starting with multicast configuration on virtual vMX routers running as VMs on VMware ESXi.

It took a lot of investigation about some part of this configuration specially the tunnel interface which you will see below. I decided to put it here all in one place with the explanation of every step because Juniper documentation tends to assume that you know more than me. If that is not the case, this short description is for you.

Here’s how the topology looks like. I have 8 routers making this topology with the plan to source multicast streams from right to left, from PC towards PC

Juniper vMX topology


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WoL – Wake On LAN

If a computer on local LAN network is turned off and administrator needs to do some regular maintenance on it, he will need to use Wake-On-LAN (WoL) to power the system up remotely.

Of course, network devices need to be configured to enable that kind of “magic” packet forwarding.

NIC cards on machines need to support WoL for this to work, but we don’t bother with this here..

WoL is sending “magic packets” to computer NIC card in order to start the system up. NIC which supports WoL is still receiving power when PC is turned off. NIC then keeps listening on the network for the magic packet and if received it will initialise the system boot process and power up the PC.

Magic packet is specially crafted network directed broadcast packet typically sent with connectionless UDP, port 7.

You would usually have a WoL server somewhere on you network which will be used to source magic packets. If you send magic packets across network segments (between VLANs or from some remote subnet), last router in the path, one having client subnet locally connected, needs to be configured with directed broadcast. The first router on the path, router with server subnet locally connected, should have ip helper configured pointing to directed broadcast IP address (in our case

In our example below, both ip helper and directed broadcast are configured on the same L3 device since this is the only router connecting two subnets.

Directed broadcast on Cisco devices is off by default since IOS 12.0 and needs to be configured on specific subnets where WoL will be needed.

You need directed broadcast because PC which needs to be woken up is asleep and while asleep it will not have an IP nor it will respond to ARP. Only way to get some packets to that PC without an ARP resolution is by using local subnet L2 broadcast.

Furthermore, we can surely assume that your PCs are connected to L2 Access Switch. That switch will not know to which port is the PC connected while that PC is asleep. Only a Layer 2 broadcast (and unknown unicast) will be sent out all ports on a switch.

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When they throw a Cisco guy to do something with HP networking gear

…There’s a nice little pdf to get you through

UPDATE on 13 Nov 2015:
It was a real pleasure to have Jeff Carell joining in with a comment about an updated version of “HP Networking and Cisco CLI Reference Guide”. Jeff is the author of “Guide to TCP/IP 4th Ed”, a great network fellow and IPv6 enthusiast whose work on informing the community about networking technology is greatly appreciated by the author of this blog. Link is added to the end of the post. Thanks Jeff.

HP is aware that most of networking engineers start their learning process in Cisco Networking Academy. Is is a normal course of events if you want to learn networking. Cisco has the very best study materials and best, carefully developed syllabus that is both high quality and most detailed in the world of networking. Not to mention the high reputation that engineers get with Cisco certificates standing by their names.

Cisco CLI

On the other hand, when you take an average mid-size business customer today you will probably see that he is mostly concerned about the price and not so much about the feature-set and robustness of IT equipment. And there you have your situation in which customer decides to go with HP rather than Cisco gear in their communication closet.

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Saving Router Configuration to Server

VoIP protocols functionalityIf you want to store a backup copy of your router’s configuration on a TFTP server we have a simple solution for you. This article will explain all the commands needed to save backup configuration of a device to TFTP server. All this for Cisco and also for Juniper device.


You need to make regular backups of your router configuration files and keep copies in a safe place. If you have a serious failure that damages a router’s hardware or software, the configuration will be destroyed. And anybody who has had to reconstruct a complex router configuration file from memory will tell you how difficult and stressful this task is. But if you have a backup of the last working configuration file, you can usually get a router working again within minutes of fixing any hardware problems.

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