Tag: OOB

Using the iPhone for Out-of-Band access

I frequently use my iPad to console onto routers as per my earlier post. But there are so much more functionality here. The iPhone can be used as a Out-of-Band device.

Why? Because it occasionally happens that a router has no device near it that can provide console access. And if you doing risky changes, this beats having to sit next to the device while doing the changes.

Requirements:

  1. A serial connector cable  (30-pin Apple to male DB9 pin RS-232).
  2. A rollover cable.
  3. A jailbroken iPhone.
  4. Terminal application.
  5. Software that supports serial communication.
  6. Inbound connectivity to iPhone Sim.

Steps 1-5 is the same as my previous post. Only difference is with step-4. The app iSSH is not needed here as the SSH connection will not be made locally from the device. So once SSH is loaded via Cydia move along to Step-5.

The last step required is having inbound access to the cellular data IP on your iPhone. This varies between cellular providers. Some providers block inbound access, others allow it by default. If your cellular provider is blocking inbound access, you will have to request them to allow it for you SIM.

All that is left to do, is plugging your phone into the distant router, (preferably locked in the cabinet, to prevent it from being stolen). From you desk SSH to the iPhone and use Minicom to reverse console into your router.

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Understanding and Configuring a HWIC-3G-GSM

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.

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Out-of-Band network

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:

  1. Low implementation cost since it is used only for support.
  2. Low monthly cost for the same reason.
  3. OOB should not depend on any existing infrastructure.
  4. Should be easily accessible from remote locations.
  5. Must be secure, since it connects to the core devices.

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)

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