Posts from ‘Written Multicast’
I recently received an email from a student with a question about an example I did in our multicast bootcamp. After an hour into testing and drafting my email response, I realized this commonly misunderstood multicast design would make a great blog writeup! The original question is as follows:
I am a customer of INE and bought the multicast bootcamp. Maybe I missed some important note, but I am confused related to the issue mentioned below. I am following the test bed you have shown in the presentation while describing the theory of sparse mode (Day 1 – Part 6) in which you have explained the RP Register, Join and SPT-Join.
Suppose the two trees are established, and traffic is flowing from the source to RP, and then RP to receiver. Also suppose that SPT-Join is disabled (e.g. threshold is infinity), and traffic always follows the shared trees.
Suppose that the multicast traffic flow is initiated from the source to the RP as follows:
R2 –> R4 –> R3 (RP)
Then traffic flows from the RP to receiver:
R3 –> R4 –>R5
When multicast traffic is coming from the RP on R4, will RPF check fail? I assume so, since multicast traffic is entering the interface in which RPF will be failed. Is there any other rule to follow if traffic is coming from RP?
After working with the December 2010 London Bootcamp on Multicast for the better part of Day 4 in our 12-day bootcamp, I returned to the hotel to find the following post on my Facebook page – “Multicast is EVIL!”
Why do so many students feel this way about this particular technology? I think one of the biggest challenges is that troubleshooting Multicast definitely reminds us of just what an “art” solving network issues can become. And speaking of troubleshooting, in the Version 4 Routing and Switching exam, we may have to contend with fixing problems beyond the scope of our own “self-induced” variety. This is, of course, thanks to the initial 2 hour Troubleshooting section which may indeed include Multicast-related Trouble Tickets.
Your very best defense against any issues in the lab exam regarding this technology – the new 3-Day Multicast technology bootcamp. Also, be sure to enjoy the latest free vSeminar from Brian McGahan – Troubleshooting IP Multicast Routing.
When we ask students “what are your weakest areas” or “what are your biggest areas of concern” for the CCIE Lab Exam, we typically always here non-core topics like Multicast, Security, QoS, BGP, etc. As such, INE has responded with a series of bootcamps focused on these disciplines.
The IPv4/IPv6 Multicast 3-Day live, online bootcamp, and the associated Class On-Demand version seeks to address the often confounding subject of Multicast. Detailed coverage of Multicast topics for the following certifications is provided:
Cisco Certified Network Professional (CCNP)
Cisco Certified Design Associate (CCDA)
Cisco Certified Design Professional (CCDP)
Cisco Certified Design Expert (CCDE)
Cisco Certified Internetwork Expert Routing & Switching (CCIE R&S)
Cisco Certified Internetwork Expert Service Provider (CCIE Service Provider)
Cisco Certified Internetwork Expert Security (CCIE Security)
To purchase the live and on-demand versions of the course for just an amazing $295 – just click here. The live course runs 11 AM to 6 PM EST US on September 29,30, and October 1.
The preliminary course outline is as follows:
- Module 1 Introduction to Multicast
Lesson 1 The Need for Multicast
Lesson 2 Multicast Traffic Characteristics and Behavior
Lesson 3 Multicast Addressing
Lesson 4 IGMP
Lesson 5 Protocol Independent Multicast
- Module 2 IGMP
Lesson 1 IGMP Version 1
Lesson 2 IGMP Version 2
Lesson 3 IGMP Version 3
Lesson 4 CGMP
Lesson 5 IGMP Snooping
Lesson 6 IGMP Optimization
Lesson 7 IGMP Security
Lesson 8 Advanced IGMP Mechanisms
A pretty important topic that is very easy to overlook when studying multicast is the PIM Assert Mechanism. After working with the TechEdit Team in the IEOC it is obvious that more than just a handful of students are confused about what this mechanism does and how it works. In this blog post (the first of many dedicated to multicasting), we will examine the PIM Assert mechanism and put this topic behind us in our preparation in mastering multicast.
In Figure 1, R1 and R4 have a route to the source 126.96.36.199 (the multicast source), and share a multi-access connection to R6. R6’s FastEthernet0/0 interface has joined the multicast group 188.8.131.52.