Greg Mahlknecht has drawn a map of the undersea communications infrastructure around the world using Microsoft Bing. I’d say it is pretty good. It gives you a good visual idea how the continents are interconnected.
Head over to his site to browse around, zoom in and out etc… http://www.cablemap.info/
How does one localise the errors on the ATM trunk to a specific VC?
Assume for a second that the following interface ATM1/0 is terminating multiple VCs (Virtual Circuits), and when you issue the following command you see CRC errors. How would you know which one of VCs are the problem child?
#show interfaces atm 1/0
ATM1/0 is up, line protocol is up
Hardware is ENHANCED ATM PA Plus
Description: bob's ATM
MTU 4470 bytes, sub MTU 4470, BW 149760 Kbit, DLY 80 usec,
reliability 255/255, txload 7/255, rxload 5/255
Encapsulation ATM, loopback not set
Encapsulation(s): AAL5
8191 maximum active VCs, 16 current VCCs
VC Auto Creation Disabled.
VC idle disconnect time: 300 seconds
Signalling vc = 1, vpi = 0, vci = 5
UNI Version = 4.0, Link Side = user
0 carrier transitions
Last input 00:00:01, output 00:00:00, output hang never
Last clearing of "show interface" counters 00:23:50
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 1115
Queueing strategy: Per VC Queueing
30 second input rate 1966000 bits/sec, 1032 packets/sec
30 second output rate 3226000 bits/sec, 1025 packets/sec
885563 packets input, 129820445 bytes, 0 no buffer
Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
350 input errors, 350 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort '<----Not cool'
1373823 packets output, 456299872 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
0 output buffer failures, 0 output buffers swapped out
Apologies for the long absence from posting. I find myself without any hours left in a day before I got to everything I wanted to do. And before you know it, more than a month has gone past.
In my previous post I presented a quick solution to an Out-of-Band network and I talked about some options. I’ve had mails asking how to show some of the configurations. I’ll cover those and do other posts I have been promising in the next couple days.
This post will focus on the current Cisco 3G WAN card, the HWIC-3G-GSM. This card is supported by Cisco’s 1841, 1861, 2800-series and 3800-series ISR routers. This card only supports High-Speed Downlink Packet Access (HSDPA) “up to” 3.6 Mb/s downlink, 384 kb/s uplink (presumably HSDPA Category 5/6, but not sure)
“3G” is a broad category of standards and services around “broadband” mobile wireless voice and data. Universal Mobile Telecommunications System (UMTS) is part of this family. High Speed Packet Access (HSPA) is a collection of mobile telephony protocols that extend and improve the performance of existing UMTS protocols. Two standards, HSDPA and HSUPA have been established and is fairly well known.
An Out-of-Band management network plays an integral part in supporting any network. Without it when core devices go down, unnecessary time is spend driving to the downed site to fix and correct the problem if remote connectivity in unavailable.
For those that don’t know, an Out-of-Band (OOB) management network is a small support network that usually runs alongside the production network at key locations, with the sole purpose to provide console level access to core devices remotely. This access can be vital to assure downtime is minimized.
The usual OOB requirements are:
ISDN and dialup technologies are most commonly used, due to the low monthly line costs. But ISDN and Dialup has the inherit cost problem if the line is connected for extended periods (days), either due engineer negligence or configuration troubles. I have also seen 64k Diginet links used, which is really not the best option cost wise, when the OOB network spans different geographical regions.
I was recently task to fix a OOB design that were using Diginet links. I looked at the design, and I cancelled all the serial links days later due to insanely high monthly costs.
Instead, to address all the required points above, I proposed a new design similar to the diagram below. (This diagram only depicts one site though)
Upgrading a 6500 is pretty straight forward, provided the necessary is done in the right order. I’ve listed the steps I would typically take to fully upgrade a single Cisco-6509-E (single Route-Processor) with a IPSEC VPN SPA blade.
Please lab this if possible BEFORE trying it in a production network. I have illustrated the steps to be taken if some of the known funnies occur during an upgrade. Feel free to use this as a guideline.
Firstly download the IOS and image versions, you need. Obviously do a little homework and check the specific IOS for known bugs using the Bug Toolkit. Don’t just pick any IOS. Make sure all the required features are relatively bug free.
Copy the downloaded files to the following locations:
I always use FTP if possible, due to the higher transfer rates. 10.3.29.239 is connected to the switch and is running a FTP server, expecting a username:password of cisco:pass.
copy ftp://cisco:pass@10.3.29.239/c6msfc3-rm2.srec.122-17r.SX5 sup-bootflash: copy ftp://cisco:pass@10.3.29.239/s72033-boot-mz.122-33.SXI2.bin bootflash: copy ftp://cisco:pass@10.3.29.239/s72033-adventerprisek9_wan-mz.122-33.SXI2.bin disk0: dir sup-bootflash: dir bootflash: dir disk0:
The second part about OVT in a previous post.
As promised, here are the slides from the presentation about OLV.
Feel free to download the slides Data-Center_Interconnect_Architecture_and_Solutions. (5mb)
I am currently attending a 2-day Cisco PVT seminar for Service Providers, where the Cisco boys are sharing some of the new and upcoming technologies and hardware on the roadmap from 2010 onwards.
Cisco Systems are where they are today because of their groundbreaking innovation.
After seeing some of the specifics and configuration, OTV really seems impressive.
What is OTV (Overlay Transport Virtualization)?
I was asked today how to calculate the Bc values. The known formulas always add confusion. So the aim of this article is not to add more confusion, but offer an easy alternate way to calculate the Bc values used with shaping.
First lets review some basic shaping definitions.
CIR (Committed Information Rate)
Tc (Time-Interval)
Bc (Committed Burst Rate)
Ever busy with a scheduled change, and the configuration all of a sudden differs from what you configured five minutes ago?
Normal IOS (not XR) behaviour allows multiple users to make instant changes to the running configuration. Occasionally two users make changes to the same config portion at the same time. One overwriting the others. ONLY the last commands entered will take effect.
The Configuration Lock feature allows a one to have exclusive change access to the Cisco IOS running configuration, preventing multiple users from making concurrent configuration changes.
There are two modes:
Ok, so an earlier post sharing a really neat geek trick is awesome, but how the hell does one go about configuring a router to tweet something? (if you not a programmer)
To do it, you would need the following:
The IOS obviously must support EEM.
Then once you have your twitter account, you need to encode your twitter account’s username:password to a base64 encoded representation. Could be done using this website. Example:
twitter-username:tweet-password
gives you
dHdpdHRlci11c2VybmFtZTp0d2VldC1wYXNzd29yZA==
Routing-Bits is now Tweeting-Bits too.
Yes I know I should have done this ages ago 
But better late than never.
Feel free to visit twitter.com/routingbits
I had a interesting question from a friend today.
Assume the following scenario:
Im going to exclude any MPLS connectivity, as it is not relevant.
The PE (Router1) connects the CE (Router3) with two links, one serial and one wireless.
This particular ISP runs mostly static routes to client sites (within the VRF’s) or alternatively eBGP.
On a wireless link it is always good practise to run BGP to detect when connectivity with the remote end is lost in the underlying Layer2 network. (Preventing a blackhole)
Regarding routing on the Serial Link, there as a default route out from Router 3 and a static route to 10.33.33.0/24 on Router1 pointing to Router3.
The client wants to load-balance traffic across both links. And the Admin Distance of the static route was set to 20 to match eBGP. (this is the scenario)
So the question : Why does Router1 not install both routes (the eBGP route and the Static), both with an prefix-length of /24, a Admin Distance of 20, and metric of 0 into the RIB??
Inspired by the flow chart that Mr Richard Bannister did for the BGP route path selection, I did one for conventional route-selection in the RIB.
I often see guys still using windows calculator to do Hex 2 Binary 2 Decimal conversions for Port numbers, Protocol numbers, DSCP values etc…
I have been using a small utility for years and have not yet come across a better one.
It was written by Live Bat Programming Group, I can’t find an official website only an email address : dagus2@geocities.com (not sure if it is still valid).
It is called HEXBINDEC (descriptive I know):
Everybody knows how to use the include|begin|exclude search operators (I hope so at least), but you can also search through config with the “/” operator. You can use this with almost any SHOW command that is more than one page long. Although similar to linux and useful it is only half as good.
I use this mostly when I want to see the configuration following a specific search string bound to show up multiple times from the SHOW command.
Example: Show the running-config, and one the first page break, hit the forward slash “/”. Now enter the string you looking for:
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