Orhan Ergun
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Orhan Ergun
BGP PIC Edge – Prefix Independent Convergence
BGP PIC Edge provides sub second convergence time in the case of edge link or node failure. BGP PIC is a useful for MPLS VPN service and can be provided by the Service provider as a value added service thus might provide additional revenue.
BFD is not a Fast Convergence mechanism !
BFD is not a fast convergence mechanism. BFD stands for Bidirectional Forwarding Detection. It is an important tool for the IP layer but there is a confusion in the network community about it.
BGP Route Reflector in Plain English
BGP Route Reflector in Plain English, in this post, I will explain you the BGP Route Reflector basics, after you read this post, you will be able to answer many questions regarding BGP Route Reflectors.
I am explaining this topic in deep detail in my Onsite CCDE , Live/Webex CCDE , Self Paced CCDE and also my specialized “BGP Zero to Hero” course.
Outline of this post is as below.
- What is BGP Route Reflector ?
- Why BGP Route Reflector is used ?
- What is the alternate methods ?
- Different type of BGP Route Reflectors
- Benefits of BGP Route Reflector
- Problems with the BGP Route Reflector
- BGP Route Reflector Redundancy
To have a great understanding of SP Networks, you can check my new published “Service Provider Networks Design and Perspective” Book. It covers the SP network Technologies with also explaining in detail a factious SP network. Click here
What is BGP Route Reflector ?
A route reflector (RR) is a network routing component for BGP (RFC 4456). It offers an alternative to the logical full-mesh requirement of internal border gateway protocol (IBGP).
Above is the wikipedia definition of BGP Route Reflector. Let’s extend the definition a bit.
BGP Route Reflector Continue reading
What does PE-CE mean in MPLS?
What does PE-CE mean in the context of MPLS ? What is CE , P and PE device in MPLS and MPLS VPN ?
These are foundational terms and definition in MPLS.
MPLS is one of the most commonly used encapsulation mechanism in Service Provider networks and before studying more advanced mechanisms, this article is must read.
In order to understand PE-CE, we need to understand first what are PE and CE in MPLS.
I am explaining this topic in deep detail in my Instructor Led CCDE and Self Paced CCDE course.
Let’s take a look at below figure.
Note: If you are looking for a much more detailed resource on this topic, please click here.
MPLS VPN PE-CE
Figure -1 MPLS network PE, P and CE routers
In Figure-1 MPLS network is shown. This can be an Enterprise or Service Provider network. MPLS is not only a service provider technology. It can provide segmentation/multi tenancy for the enterprise environment as well.
Three different types of router are shown. CE , PE and P routers.
CE devices are located in the customer site. PE and P devices are located in the Service Provider site.
If it is Enterprise network, WAN Continue reading
BGP Route Reflector Clusters
BGP route reflectors, used as an alternate method to full mesh IBGP, help in scaling.
BGP route reflector clustering is used to provide redundancy in a BGP RR design. BGP Route reflectors and RR clients create a cluster. (Cluster = BGP RR + BGP RR Clients)
I am explaining this topic in deep detail in my Onsite CCDE , Live/Webex CCDE , Self Paced CCDE and also my specialized “Live/Webex BGP Zero to Hero” course.
In IBGP topologies, every BGP speaker has to be in a logical full mesh. So, every BGP router has to have a direct IBGP neighborship with each other. However, route reflector is an exception.
If you place a BGP Route Reflector , IBGP router sets up BGP neighborship with only the route reflectors.
In this article, I will specifically mention the route reflector clusters and its design.
For those who want to understand BGP Route Reflectors, I highly recommend my ‘ BGP Route Reflector in Plain English ‘ post.
If you want to learn Route Reflector Loop Problem , check this post
Also, I explained BGP Route Reflectors, Route Reflector Design Options and many other Service Provider Design topic in my Service Provider Design Workshop.
Webinar, Podcast And Free Videos
DMZ Anywhere Architecture – Webinar
In this webinar Orhan Ergun and Ahmed Al-Deeb are talking about DMZ Anywhere architecture. Micro Segmentation , Deploying DMZ in a virtual environment to reduce cost, providing flexibility and better performance will be highlighted.
www.orhanergun.net DMZ Anywhere Webinar
Mobile Broadband Basics – Webinar
In this webinar Orhan Ergun and Karim Rabie is talking about Mobile broadband technologies basics. 2G, 3G,4G,LTE and 5G is explained by Mobile Broadband expert Karim Rabie.
Sessions slides will be uploaded shortly.Introduction to Mobile Broadband- 2G, 3G, 4G, LTE and 5G Technology basics
Global CCDE List
Global CCDE List
How many CCDEs are there in the world? What country has the most CCDEs? How do you become a CCDE Global List member? You can find out the answers to these questions below. If you have a CCDE number, if you changed your country or company share it in the comment box below or contact me directly. This list will be updated as soon as new members are accredited. You can be the one of them.More than 60 of these CCDEs passed the exam after Orhan Ergun’s CCDE bootcamp.
Check Orhan Ergun’s CCDE Training Program
Total Number of CCDE: 430
| Top Companies | Top Countries | Lady CCDE (4 CCDE) |
| Cisco (94 CCDE) | U.S (105 CCDE) | Denise Fishburne |
| Conscia (8 CCDE) | U.K (22 CCDE) | Louise Simmons |
| AT&T (5 CCDE) | Germany (13 CCDE) | Lauren Child |
| Dimension Data (4 CCDE) | UAE (11 CCDE) | Irene Salas |
| VMware (4 CCDE) | Australia (9 CCDE) |
GLOBAL CCDE LIST
| Name | Company | Number | Country |
| Russ White | Ericsson | 20070001 | US |
| John Cavanaugh | NetCraftsmen | 20070002 | US |
| Bruce Pinsky | Intuit | 20070003 | US |
| Khalid Raza | Viptela | 20070004 | US |
| William Parkhurst | Soliel | 20070005 | US |
| Alvaro Retana | Cisco | 20070006 | US |
| Mosaddaq Turabi | Viptela | 20070007 | US |
| Steve Barnes | 20070008 | ||
| Continue reading |
4 Main Design Principles of Mobile Networks
4 Main, Key Design Principles of Mobile Networks – I will explain the 4 key design principles of cellular networks in plain English.
In fact I should have said, cell based systems as mobile networks may not be design based on cell based architecture.
Let me explain what would be the other deployment option for the mobile network, other than cell based systems and then will highlight the 4 main characteristics of cell based mobile networks.
Before, cellular systems designed, mobile network operators used to place their radio transmitters at the tallest buildings in the area which they want to provide a coverage. Single, very high-power transmitters was used to cover very large geographic areas.
With the cell based telephone systems, so many low-power, small coverage area transmitters are used instead of a single, powerful, monolithic transmitter to cover a wide area.
This is first design principles of cell based mobile phone networks.
Second design principle of cell based systems is frequency reuse.
I hared a post on wireless frequency spectrum allocation problem here. Read it as well, if you want to understand the limit and the problems of electromagnetic frequency spectrum.
The second design principle which is frequency reuse, takes Continue reading
MANET: Mobile Ad Hoc Networks
The MANET stands for mobile ad hoc network; in practice, the term generally applies to ad hoc wireless networks of sufficient complexity that some internal routing mechanism is needed to enable full connectivity.
The term mesh network is also used for MANETs.
MANET nodes communicate by radio signals with a finite range, as in the Figure – 1 below.
Each node’s radio range is represented by a circle centered about that node. In general, two MANET nodes
may be able to communicate only by relaying packets through intermediate nodes, as is the case for nodes
A and G in the diagram above.
Mobile Ad Hoc networks can use any wireless mechanism
In the field, the radio range of each node may not be very circular, due to signal reflection. An additional complication arises when the nodes (or even just obstructions) are moving in real time (hence the “mobile” of MANET); this means that a working route may stop working a short time later.
For this reason, routing within MANETs is a good deal more complex than routing in an Ethernet. A switched Ethernet, for example, is required to be loop-free, so there is never a choice among multiple alternative routes.
MANETs in general do not support broadcast, Continue reading
Wireless ISPs Spectrum Problem
Wireless ISPs also known as WISP mostly use unlicensed frequency spectrum. Frequency spectrum is the most critical asset for the Mobile and Wireless networks and it is sold in auctions for 100s of millions of dollars.
Frequency spectrum is managed by the governments and governments in general, sell frequency spectrum in auctions.
And some frequencies are really expensive, I am talking about 100s of millions of dollars. But frequency spectrum is so important ? Why it is a problem with Wireless Internet Service Providers ? What is Wireless Internet Service Provider in the first place ? I explain all these questions during my Telecom Training but I wanted to share below post with you.
Below you will find a very nice write up from one of the founding members of the Wireless Internet Service Providers Association (WISPA).
Although it is written for the U.S government, situation is the same in every country for the Wireless Internet Service Providers.
Congress – Stop Selling Our Airwaves!
by John Scrivner
Do you have little or no access to broadband (high speed) Internet? Then forward this note to your Congressman to get this fixed.
Broadband is something most Americans take for granted. That is unless Continue reading
GRE Tunnels – Generic Routing Encapsulation – Use Cases
GRE Tunnels
GRE tunnels are by far most common tunnelling technology. Very easy to setup, troubleshoot and operate. But in large scale deployment, configuring GRE tunnels become cumbersome, because GRE tunnel is a point to point tunnel.
GRE Tunnel Characteristics
• GRE tunnels are manual point to point tunnels. Tunnel end points are not automatically derived. Network operator needs to configure the tunnel end points manually.
• Supports routing protocols to run over. You can run any routing protocols on top of GRE tunnels.
• IPv4 and IPv6 can be transported over GRE. Some VPN technologies may not support IPv6 or IPv6 routing protocols.
• Non-IP protocols such as IPX, SNA etc. can be carried over GRE tunnel as well. Most of the tunnelling technologies cannot carry Non- IP traffic. For example, IPSEC tunnel cannot carry Non-IP Traffic.
• If there are too many sites that need to communicate with each other, GRE is not scalable. But in Hub and Spoke topologies it can be used since whenever new spoke site is added, only new site and hub should be revisited. Not all the spokes need configuration.
• Even though in Hub and Spoke topologies, the configuration can be too long on the Continue reading
Introduction to VPN (Virtual Private Network)
Introduction to VPN (Virtual Private Network)
Let’s start with the definition. VPN is a logical network and created over shared physical infrastructure.
Shared infrastructure can be private such as MPLS VPN of a Service Provider or over the Public infrastructure such as Internet.
There are many concepts to understand VPN in detail but in this article I will cover the definition, common design considerations, and some not well known concepts about it.
We can group VPNs into two categories. WAN and the Datacenter VPN Technologies.
WAN VPN Technologies
1.GRE
2.mGRE (Multipoint GRE)
3. IPSEC
4. DMVPN
5.GETVPN
6.L2TPV3
7.LISP
8. MPLS L3 VPN
Datacenter VPN Technologies
1.EoMPLS (Ethernet over MPLS (a.k.a VPWS)
2. VPLS (Virtual Private Lan Service)
3. OTV (Overlay Transport Virtualization)
4. EVPN
5. PBB-EVPN
6. VXLAN (And other host based overlays such as NVGRE, STT, GENEVE)
Of course this is not the complete list. Please note that some of the technologies which I grouped into WAN technologies can be used in the Datacenter and vice versa.
For example LISP can be used in Datacenter as well and VPWS and VPLS can be used on the Wide Area Network as well.
Should I use Cisco OTV for the Datacenter Interconnect ?
Should I use Cisco OTV for the Datacenter Interconnect? This question comes from not only from my students but also the companies which I provide consultancy.
I will not go through the OTV details, how it works, design recommendations etc. But let me remind you what is OTV and why OTV is used , Where it makes sense very briefly.
OTV (Overlay Transport Virtualization) is a tunnelling mechanism which provides to carry Layer 2 ethernet frame in IP. (As I indicated in other articles, when I say MAC in IP, it is the same thing with MAC over IP).
So, OTV is Layer 2 in Layer 3 tunnelling mechanism. You can hear it is an encapsulation mechanism as well, which is true although there is small difference.
You don’t need to have MPLS underlay to create OTV tunnels. It uses IS-IS for the MAC address reachability and stops layer 2 protocol PDUs at the OTV Edge device where encapsulation happens.
This is good because, you don’t want to extend Layer 2 protocol PDUs such as Spanning Tree if you have multiple datacenters. Failure stays and affects only one datacenter, not all. (Failure domain boundary concept)
Another datacenter interconnect requirement Continue reading
Carrier Ethernet – Definition | Service Types | Requirements
CARRIER ETHERNET DEFINITION
Carrier Ethernet is an attempt to expand Ethernet beyond the borders of Local Area Network (LAN), into the Wide Area Networks (WAN).
With Carrier Ethernet, customer sites are connected through the Wide Area Network. Carriers have connected the customers with ATM (Asynchronous Transfer Mode) and Frame Relay interfaces in the past. (User to Network Interface/UNI).
Carrier Ethernet is not about the Ethernet within the Local Area Networks.
Driver of Carrier Ethernet is; since Ethernet is the de-facto protocol on the Local Area Network, why not to use Ethernet everywhere, and not only within LAN. When any other Wide Area Network protocol is used such as ATM, customer Ethernet frame is encapsulated into another protocol.
This reduces the overall efficiency of customer service, consumes more network bandwidth, makes troubleshooting harder and many other drawbacks.
Carrier Ethernet is also known as Carrier Class Ethernet and Carrier Grade Ethernet.
Another reason for Carrier Ethernet is; Ethernet interfaces and the devices are cheaper compare to the other technologies. This result cheaper service to the customers.
CARRIER ETHERNET REQUIREMENTS
Traditional Ethernet lacks many features which are required to transport critical services, time sensitive applications and voice services.
These are:
- Traffic Engineering
- Bandwidth Guarantee
- Quality of Service
- OAM
- Decoupling of Providing and Customer Networks
- Continue reading
What is Colocation, POP , Carrier Hotels and Meetme Room ?
What is Colocation, POP , Carrier Hotels and Meetme Room ?
If you are working in operator domain or a network engineer who wants to learn what is colocation , what is POP (Point of Presence) , how POPs are physically connected , POP terminology , understand meetme room and carrier hotel, this post is for you.
POP locations can be located in the Datacenter or in very small buildings , meetme room and the carrier hotel is placed in the datacenter.
Colocation is provided by the datacenters.
But there are other details which you should be aware.
I explained these details in the below video. This video is one of the 20 topics from the network interconnection module of Service Provider Design Workshop. You can take this workshop and watch the on demand 10+hours service provider technology videos right away.
If you are not a subscriber yet ,you should subscribe to youtube channel right now.
If you any question or comment, please share in the comment box below.
Orhan Ergun
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Real Life Financial Network Design – Multicast – BGP – EIGRP – Latency Design Considerations
I was in London last week for CCDE Training. During the training, there was a discussion on Financial network design and one of the students explained how they designed their financial world-wide network. We recorded the discussion and I think you will get great benefit if you want to understand how financial networks are designed, …
The post Real Life Financial Network Design – Multicast – BGP – EIGRP – Latency Design Considerations appeared first on Cisco Network Design and Architecture | CCDE Bootcamp | orhanergun.net.
New book on LISP – Locator and Identity Separation Protocol
New book is released on LISP – Locator and Identity Separation Protocol. “LISP Network Deployment and Troubleshooting: The Complete Guide to LISP Implementation on IOS-XE, IOS-XR, and NX-OS” I still couldn’t start to read it as the authors didn’t send my own copy yet :), but I want to congratulate the authors, Tarique, Vinit and …
Continue reading "New book on LISP – Locator and Identity Separation Protocol"
The post New book on LISP – Locator and Identity Separation Protocol appeared first on Cisco Network Design and Architecture | CCDE Bootcamp | orhanergun.net.
What is last hop router and first hop router in Multicast?
What is last hop router and first hop router in Multicast? These are important terms which are used in Multicast. In this post, I will explain the terms, differences and some detail about this term. In fact, last hop router and the first hop router can be considered as the same thing. But I …
Continue reading "What is last hop router and first hop router in Multicast?"
The post What is last hop router and first hop router in Multicast? appeared first on Cisco Network Design and Architecture | CCDE Bootcamp | orhanergun.net.
Recommended Networking Resources for September 2019 Third Week
There are so many good resources for Network Engineers out there. I started to share the ones I liked on beginning of this month. Click here to see previous Networking Recommended Resources. As you know, I share 5 resource every week. There are so many in my list already, I can’t wait for the next …
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The post Recommended Networking Resources for September 2019 Third Week appeared first on Cisco Network Design and Architecture | CCDE Bootcamp | orhanergun.net.
Recommended Networking Resources for September 2019 Second Week
There are so many good resources for Network Engineers out there. I started to share the ones I liked last week. Click here to see September 2019, First Week Networking Recommended Resources. As you know, I will share 5 resource every week. There are so many in my list already, I can’t wait for the …
Continue reading "Recommended Networking Resources for September 2019 Second Week"
The post Recommended Networking Resources for September 2019 Second Week appeared first on Cisco Network Design and Architecture | CCDE Bootcamp | orhanergun.net.