Monthly Archives: August 2016

Episode 11 – Infrastructure Lifecycle

We returned to record our eleventh episode on Sunday August 28, 2016.

Interesting News and Events

Roundtable Discussion – Infrastructure Lifecycle


Reasons for a refresh?

  • End of Life (EoL)
  • End of Support (EoS)
  • Performance
  • Expansion
  • Budgeting (new equipment might be less costly than maintaining older equipment under maintenance contracts)
  • New features requirement (PoE+ vs PoE / 10Gbps vs 1Gbps / 1Gbps vs 100Mbps)
  • Manageability

Strategic Lifecycle Planning – often companies plan and budget to replace their infrastructure every 5 – 7 years.

What kind of refresh ?

  • The easy one; 1:1 like e.g. one core switch for a newer cores witch
  • Technology change; like e.g. from classic STP to multi chassis link aggregation
  • Fabrics
  • Software Defined Networking

You can really stretch the budget by looking at second hand equipment, especially for non-critical sections of the infrastructure. Avoid grey market equipment and only work with a reputable vendor.


Reach out for the Vendors:

  • Educate yourself before the vendors show up
  • Compare different vendors and technologies with each other
  • Document the features that you are looking for in the solution
  • Proof of Concept – prove out the possible solution
  • Rollout Planning
  • Maintenance window – new product gets implemented to the production environment
  • Finger crossed (look for bugs)

What tools are you using?

Synergy – Synergy combines your desktop devices together into one cohesive experience. It’s software for sharing your mouse and keyboard between multiple computers on your desk. It works on Windows, Mac OS X and Linux. It’s only $10 for the basic version and well worth the money in Dominik’s opinion.

Michael’s technical challenge?

T460-heroThese past two weeks I’ve been working to figure out why the Lenovo ThinkPad T460 w/Intel AC 8260 wireless adapter wasn’t playing well with a Cisco 5508 Wireless LAN Controller and Cisco 1262N and 3702E Access Points. The device itself is pretty nice… very thin, not very heavy, great keyboard and doubles as a tablet. I’ll be sad to give it up when I figure out what’s broken. Watch my blog for a follow-up and possible conclusion.

Update: August 30, 2016 – workaround is to enable A-MPDU for 802.11n – Lenovo ThinkPad T460 Yoga with Intel AC 8260 Wireless Issues


Episode 10 – IPv6 Internet Addressing

We returned to record our tenth episode on Sunday August 21, 2016.

Interesting News and Events

Roundtable Discussion – IPv6

IPv4 provides an addressing capability of 232 or approximately 4.3 billion addresses
RFC 791 September 1981

Issues with IPv4 addressing:

  • not enough available address space
  • all blocks are already provisioned
  • conflicting IPv4 addressing between networks requires NAT


Grey/Black market for IPv4 Address space;

Microsoft pays Nortel $7.5 million for IPv4 addresses – Bankrupt Nortel finds a buyer for 666K of its legacy IPv4 addresses, raising questions if the IPv4 black/grey market has arrived.

Cellular Mobile 3G/4G Networks – Carrier NAT

Local Internet Registry

IP NG  – early working-group proposals
The Internet Engineering Task Force adopted the IPng model on 25 July 1994, with the formation of several IPng working groups.[4] By 1996, a series of RFCs was released defining Internet Protocol version 6 (IPv6), starting with RFC 1883. (Version 5 was used by the experimental Internet Stream Protocol.)
IPv6 Addresses -128Bit 3.4×10^38 addresses

Just how many IPv6 addresses are there? Really?

Subnet Cheat Cheat

Usage Statistics of IPv6

Address Types

  • Unicast
  • Multicast
  • Anycast

Dual-Stack IPv6 Use cases:

  • Management networks
  • home net / Mobile Laptop connectivity via IPv6 Tunnel
  • mergers , change the subnet / prefix on the fly

IPv6: Privacy Extensions

  • Stateless address autoconfiguration (SLAAC)

Neighbor Discovery

What is no longer available?

  • NAT
  • packet fragmentation by routers >> MTU path discovery has to be working for IPv6
  • Broadcast

IPv6 Issues and Problems (IPv6 Multicast Listener Flooding) (Garrett Wollman)

How to check IPv6 connectivity
The Turtle is dancing –

Who is already available in IPv6? More than you think, Google, Facebook and many other large web centric companies.

Tunnel Mechnaism:
Free 4to6 Tunnel broker: >> Hurricane Electric
IPv6 traffic is encapsulated into IPv4 using IPv6-in-IP, UDP (Teredo), or Intra-Site Automatic Tunnel Addressing Protocol (ISATAP)

IPv6 Cheat sheat –

Naming IPv6 address parts – Proposed IETF RFC and a VOTE – chazwazza