Posts Tagged ‘practice’
Today’s CCENT-level challenge involves the methods that are commonly used to describe and compare modern network infrastructures regarding such things as performance and structure.
ICND1-1: What common descriptive characteristic for a modern network often encompasses a measure of the probability of a network failure called the Mean Time Between Failures or MTBF?
In our recent Implement Layer 2 Technologies series, we examined Q-in-Q tunneling in great detail. In this discussion, I mentioned a big caution about the Service Provider cloud with 802.1Q trunks in use for switch to switch trunking. This caution involved the use of an untagged native VLAN.
You see, this configuration could lead to what is known as the VLAN hopping attack. Here is how it works:
- A computer criminal at a customer site wants to send frames into a VLAN that they are not part of.
- The evil-doer double tags the frame (Q-in-Q) with the outer frame matching the native VLAN in use at the provider edge switch.
- The provider edge switch strips off the outer tag (because it matches the native VLAN), and send this frame across the trunk.
- The next switch in the path examines the frame and reads the inner VLAN tag and forwards the frame accordingly. Yikes!
Notice the nature of this attack is unidirectional. The attacker can send traffic into the VLAN, but traffic will not return. Admittedly, this is still NOT something we want taking place!
What are solutions for the Service Provider?
- Use ISL trunks in the cloud. Yuck.
- Use a Native VLAN that is outside of the range permitted for the customer. Yuck.
- Tag the native VLAN in the cloud. Awesome.
You will find the answer to today’s CVOICE Exam Practice in the comments area of the blog approximately 24 hours after the post. Have fun!
CVOICE-1: Cisco Unified Communications gateways support various VoIP signaling protocols. For each description below, provide the signaling protocol that is described:
A. This protocol specifies the commands and responses to set up and tear down calls. It also details features such as security, proxy, and transport control protocol (TCP or User Datagram Protocol [UDP]) services. It is a text-based protocol that borrows many elements of HTTP, using the same transaction request-and-response model and similar header and response codes.
B. This protocol definition controls VoIP gateways that are connected to external call control devices, referred to as call agents.
C. This standard specifies the components, protocols, and procedures that provide multimedia communication services—real-time audio, video, and data communications—over packet networks, including IP networks. The protocol is part of a family of ITU-T recommendations.
D. This Cisco proprietry protocol is used between Cisco Unified Communications Manager and Cisco Unified IP phones.
Beginning January 17th, 2011, Cisco will add Layer 2 Switch Troubleshooting to the 2 hour Troubleshooting section of the lab exam. Like the Layer 3 Troubleshooting that you will perform, these switches are emulated devices using Cisco’s IOU product – that stands for IOS on UNIX and is a similar approach to the popular Dynamips platforms. Cisco calls the ability to emulate switches on UNIX – L2IOU.
As you know, INE has been addressing Layer 2 Troubleshooting in all of our CCIE R&S products for a long time – so there will be few modifications that need to be made. I realize that change does cause some level of fear among students studying hard for this exam. I will be sure to schedule a free vSeminar next week to chat about this latest exam format and answer your questions. Watch the blog for the date and time of that vSeminar.
By the way, Cisco announced this change on the Cisco Learning Network this week. Here is the original post.
One of the most important technical protocols on the planet is Open Shortest Path First (OSPF). This highly tunable and very scalable Interior Gateway Protocol (IGP) was designed as the replacement technology for the very problematic Routing Information Protocol (RIP). As such, it has become the IGP chosen by many corporate enterprises.
OSPF’s design, operation, implementation and maintenance can be extremely complex. The 3-Day INE bootcamp dedicated to this protocol will be the most in-depth coverage in the history of INE videos.
This course will be developed by Brian McGahan, and Petr Lapukhov. It will be delivered online in a Self-Paced format. The course will be available for purchase soon for $295.
Here is a preliminary outline:
Day 1 OSPF Operations
● Dijkstra Algorithm
● Neighbors and Adjacencies
○ OSPF Packet Formats
○ OSPF Authentication
○ Link-State information Flooding
INE is happy to announce a new class dedicated to the recently introduced Cisco Certified Design Expert (CCDE) certification. The first CCDE Practical Bootcamp is to be run on May 1-5th in Chicago, right before the actual CCDE practical exam that is scheduled on May 6th. Our goal was designing a “last-week” refresher and booster class to finalize your CCDE exam preparation. Students are assumed to have solid theoretical knowledge of the exam’s technology base prior to attending. This blog posts gives you a quick overview of the class structure and pre-requisites you should meet in order to benefit the most from this training offer.
Join me tomorrow, October 22nd at 12:00 PM PST / 3:00 PM EST, for the free vSeminar: Unified Mobility Interactions with Local Route Group and Globalization.
To attend this free vSeminar, use the following URL tomorrow at 12:00 PM PST / 3:00 PM EST: Unified Mobility Interactions with Local Route Group and Globalization
In case you missed any previous vSeminars, be sure to check out the recent updates here.
If you are interested in learning more about technologies covered by the CCIE Voice Lab Exam, check out INE’s Voice Deep Dive. The CCIE Voice Deep Dive is the ideal way to gain in-depth knowledge about specific topics and technologies. We’ve now just completed 17 modules, and unlike other Class on Demand’s that only go to 20 or possibly 25 hours, ours now span over 95 hours of training, and we still have more to go. It truly doesn’t get any “deeper” than this. We will post an update with the complete new table of contents to these 3 newly released Deep Dive modules on CUCME, next week.
Hope to see you tomorrow!
CCIE instructors see the question time and time again – are we penalized for “over-configuration” in the CCIE lab exam? The answer – “not typically”. Let us walk through some examples to see exactly what we are talking about here.
First of all, I encourage students to ask two questions when they are about to “over-configure” something. Question 1 – can this additional configuration I am about to make actually gain me points (might Cisco be grading for it)? Question 2 – can this additional configuration I am about to make actually hurt me (cause point loss)? If the answers are a resounding YES and NO, then it is definitely a configuration you should consider making.
Encoding and Modulating
What form of CSMA does 802.11 use?
What does DCF stand for?
Your wireless station heres someone transmit and waits the duration heard plus what value?
What logically seperates WLANs?
Name three requirements to roam between two autonomous APS.
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