“But it gave the impression of the sort of good idea!” How usually have we heard this in the midst of combating the chaos monster we created for ourselves? In this newsletter, I’m going to talk about an instance of this from my time with a former company, who shall continue to be anonymous to keep away from the disgrace.
As a community engineer for a former employer, considered one of my principal assignments become the buildout of a huge SONET fiber optic network. The SONET community used Lucent Metropolis DMX multiplexers to hold each TDM offerings (DS1/DS3) and rapid and gigabit Ethernet. This changed into a prime upgrade that replaced a ramification of older Cisco routers and a web of factor to factor hyperlinks inside the middle of the community. As the buildout advanced, a business selection became made that a part of the community could no longer be finished or delayed in final touch. This changed into a logical business choice that induced a sequence of terrible era decisions in an attempt to deal with it.
The nature of a SONET network is that it’s far meant for use in a ring. This offers redundancy, in case of one break within the ring, traffic will nevertheless continue to waft uninterrupted. In this case, we are left with an incomplete broken ring because of the lacking portions. Now it’s time for the second one chaos inducing enterprise decision, we MUST close the hoop and do it with minimal to 0 fee.
So now we’re at the first attempt. There changed into present fiber in vicinity from an workplace element manner up one “horn” to the quit of the second one “horn”. The fiber become out of spec to run the OC48 SONET hyperlinks however it was adequate to run 100Base-FX Ethernet. So, the primary strive became to tie an Ethernet port on both ends collectively with this fiber hyperlink and near the ring. Unfortunately, this wasn’t such a exact idea. Lucent, of their information, had neglected to put into effect spanning tree protocol on the DMX Ethernet transfer ports (simplest the digital port connecting the Ethernet switch to the SONET ring had STP). This resulted in a huge and immediate STP loop and interrupted provider for approximately sixty five,000 people for 10 minutes.
The second try become to insert a Cisco 2924 Ethernet transfer inside the link and permit the 2924’s STP to break the loop. This idea worked perfectly in testing and labored flawlessly on installation.
Unfortunately, someday later, the community all over again skilled an STP loop with corresponding service outage. I attributed this to the reality that the 2924 wasn’t aware of the STP network of the DMX Ethernet switches and vice versa and that they were making impartial choices that could war.
Third strive became to chop up the SONET community, the usage of scarce and expensive Ethernet ports on the DMXs and reinserting the old Cisco routers. At this point, I decided a mutual parting of the approaches changed into suitable, given in which I may want to see this turned into heading. We had taken an elegant, kingdom of the artwork, SONET community and mutilated it in an try to patchwork it, developing an unwell appearing and unsupportable monster. To say that this will had been a nightmare would not say sufficient. The configuration became some distance from some thing intended via Lucent.
This illustrates the threat of allowing collectively conflicting commercial enterprise decisions made without good enough consideration of the results to force a a chain of determined patches to vital network systems for you to compensate. This induced lost revenue for the company, misplaced purchaser precise will, and loss of popularity. Ironically, I accept as true with that, ultimately, it might were less expensive to have finished the authentic task.
The ethical of this? Consider cautiously the REAL fee of technology affecting decisions, each in terms of money and impact on customer support. Don’t make assumptions approximately the capability of your network to soak up unconventional adjustments in configuration. Make sure you apprehend all of the viable downsides. Consult with an experienced network engineer.