Studying for the CCIE RS Written and Lab – EIGRP Stub

January 13, 2018 at 12:41 pm

Challenges

In this video, Anthony Sequeira gives a tip on how we should consider preparing for the CCIE written and lab exams simultaneously.

400-101 CCIE R&S Written – Free Resources – UDP Operations

January 6, 2018 at 11:28 am

UDP

If a TCP session is like a phone call – then a UDP transmission is like a postcard! Here are the free study resources around UDP!

1.1.f Explain UDP operations
1.1.f [i] Starvation
1.1.f [ii] Latency
1.1.f [iii] RTP/RTCP concepts

The UDP Protocol

UDP Broadcast Flooding

Defending Against Distributed DoS Attacks

IP SLA Configuration Guide

RTP

CCIERS

CCIE R&S Prep Club – Preregistration

January 2, 2018 at 9:59 pm

Are you one of the readers that are planning to sign up for CCIE R&S Personal Training here at AJSnetworking.com? Preregistration for this service is now available. This provides our trainer(s) with an opportunity to get to know you and your current status with CCIE R&S studies. Please only complete the form using the link below if you actually plan on signing up for the service.

Here is the link for pre-registration:

CLICK HERE TO PREREGISTER! 

400-101 CCIE R&S Written – Free Resources – TCP Operations

December 30, 2017 at 9:48 am

TCP

Here are the free resources surrounding the Explain TCP Operations section of the CCIE R&S Written version 5.1 exam.

1.1.e Explain TCP Operations

  • 1.1.e.i     IPv4 and IPv6 PMTU
  • 1.1.e.ii    MSS
  • 1.1.e. iii  Latency
  • 1.1.e. iv  Windowing
  • 1.1.e.v    Bandwidth delay product
  • 1.1.e.vi   Global synchronization
  • 1.1.e       Options

TCP Performance – The Internet Protocol Journal – Volume 3, No. 2

Resolve IP Fragmentation, MTU, MSS, and PMTUD Issues with GRE and IPSEC

IP Application Services Configuration Guide, Cisco IOS Release 15M&T

IPv6 Addressing and Basic Connectivity Configuration Guide, Cisco IOS Release 15M&T

IP SLAs Configuration Guide, Cisco IOS Release 15M&T

TCP Options

TCP Global Synchronization 

TCP/IP Illustrated, Volume 1

CCIERS

Rapid Spanning Tree Protocol (RSTP) 802.1w

December 29, 2017 at 8:10 am

rstp

Whether you are pursuing your CCNA, CCNP, CCIE, or many other Cisco Certifications, a deep knowledge of RSTP is critical. In this post, we will detail key facts for you regarding this Layer 2 loop prevention system.

  • 802.1w (RSTP) is an evolution of the classic 802.1D (STP) protocol
  • 802.1D tried to speed things up with the additions of UplinkFast, BackboneFast, and PortFast; the UplinkFast and BackboneFast features are now essentially built into RSTP, while PortFast is still a feature you enable in RSTP if desired
  • 802.1w can also revert back to 802.1D in order to interoperate with legacy bridges on a per-port basis
  • With 802.1D, once in the forwarding state, there is no way to tell from the port state whether the port is root or designated; RSTP decouples the role and the state of a port to address this issue
  • The 802.1D port states are Disabled, Blocking, Listening, Learning, Forwarding; in 802.1w these are simplified to Discarding, Learning, Forwarding
  • The port roles are expanded in 802.1w to include Backup and Alternate ports in addition to Root and Designated; these new port roles help implement the features of UplinkFast into the protocol natively
  • A Backup port receives more useful BPDUs from the same bridge it is on and is a port blocked
  • An Alternate port receives more useful BPDUs from another bridge and is a port blocked
  • RSTP now uses all six bits of the flag byte that remain in order to perform – encoding the role and state of the port that originates the BPDU and handling the proposal/agreement mechanism
  • The RSTP BPDU is now of type 2, version 2; legacy bridges must drop this new BPDU; this makes it easy for an 802.1w bridge to detect legacy bridges connected to it
  • BPDUs are sent every hello-time, and not simply relayed anymore’
  • BPDUs are now used as a keep-alive mechanism between bridges; a bridge considers that it loses connectivity to its direct neighbor root or designated bridge if it misses three BPDUs in a row; this fast aging of the information allows quick failure detection
  • To natively support the BackboneFast type behavior, RSTP accepts inferior BPDUs; when a bridge receives inferior information from its designated or root bridge, it immediately accepts it and replaces the one previously stored; this permits fast acceptance of a new Root port in the topology
  • Rapid transition is the most important feature introduced by 802.1w; RSTP is able to actively confirm that a port can safely transition to the forwarding state without having to rely on any timer configuration; in order to achieve fast convergence on a port, the protocol relies upon two new variables: edge ports and link type
  • RSTP can only achieve a rapid transition to the forwarding state on edge ports and on point-to-point links; the link type is automatically derived from the duplex mode of a port
  • A proposal/agreement process in RSTP aids in very convergence
  • The topology change notification process is overhauled in order to also aid in faster convergence and improve efficiency

For more details on these new features summarized here – check out Understanding Rapid Spanning Tree Protocol (802.1w) This document often forms the basis for plenty of RSTP-related written exam questions from CCENT to CCIE. Note that my summary document here covers most of those questions for you, however!

criers