OTV AEDs Are Like Highlanders
While prepping for CCIE Data Center and playing around with a lab environment, I ran into a problem I’d like to share.
I was setting up a basic OTV setup with three VDCs running OTV, connecting to a core VDC running the multicast core (which is a lot easier than it sounds). I’m running it in a lab environment we have at Firefly, but I’m not going by our normal lab guide, instead making it up as I go along in order to save some time, and make sure I can stand up OTV without a lab guide.
Each VDC will set up an adjacency with the other two, with the core VDC providing unicast and multicast connectivity. That part was pretty easy to setup (even the multicast part, which had previously freaked me the shit out). Each VDC would be its own site, so no redundant AEDs.
On each OTV VDC, I setup the following as per my pre-OTV checklist:
- Bi-directional IPv4 unicast connectivity to each join interface (I used a single OSPF area)
- MTU of 9216 end-to-end (easy since OTV requires M line cards, and it’s just an MTU command on the interface)
- An OTV site VLAN which requires:
Using Big Tools for Small Problems
BGP in the data center? And MPLS? Are you insane? Well, maybe, yes. But then again, I’ve been known to do a lot of crazy things in my time. Isn’t MPLS a core and edge service provider technology, while VXLAN is an enterprise data center technology? But let’s begin with this idea that technologies are […]
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Running RIPv2 with INE Topology with IOU/IOL
The Problem or Task I wrote the initial topology introduction on INE’s topology with IOU here. Task Enable RIPv2 on all 155.1.0.0 and 150.1.0.0 interfaces and disable auto-summary. Seems simple...[[ Summary content only, you can read everything now, just visit the site for full story ]]
Replacing an MPLS WAN with an Internet VPN Overlay
I received an email last week from a reader seeking advice on a fairly common predicament:
Our CIO has recently told us that he wants to get rid of MPLS because it is too costly and is leaning towards big internet lines running IPSEC VPNs to connect the whole of Africa.
As you can imagine, this has caused a huge debate between the networks team and management, we run high priority services such as Lync enterprise, SAP, video conferencing etc. and networks feel we need MPLS for guaranteed quality for these services but management feels the Internet is today stable enough to run just as good as MPLS.
What is your take on the MPLS vs Internet debate from a network engineer's point of view? And more so, would running those services over Internet work?
This is something I struggled with pretty frequently in a prior job working for a managed services provider. MPLS WANs are great because they provide flexible, private connectivity with guaranteed throughput. Most MPLS providers also allow you to choose from a menu of QoS schemes and classify your traffic so that real-time voice and video services are treated higher preference during periods of congestion.
Unfortunately, Continue reading
Reboot & update your router in half the time with warm reloads!
Reloading a router can sometimes feel right like an eternity, usually when you issue a reload you can step away get a cup of coffee sit back down and the router should be just about be ready. For quite a while now (well since before 12.4 which lets admit is a long time ago) we’ve […]
Brazil’s Winning Internet
Another World Cup is in the books, and it’s fair to say that most people will remember 2014 for the inglorious and improbable performance of the host nation, losing 7-1 and 3-0 in its semifinal and consolation matches. Brazil’s sad exit capped off a year of soul-searching about the nation’s massive investment in hosting the World Cup (and the Olympics yet to come).
But Brazil shouldn’t lose sight of one important silver lining to their World Cup cloud: the startlingly vibrant development of the Brazilian Internet, and the critical role Brazil now plays in the Internet connectivity and ICT development of South America.
| Preparations for the World Cup and the Olympics may have helped light a fire under Brazil’s Internet infrastructure providers. Here’s a plot of the growth of the set of autonomous systems (that is, enterprises and service providers who originate IPv4 address space under their own registered Autonomous System Number) in Brazil over time. For comparison, we’ve also included the same statistic for South Africa. By this measure, the two World Cup host countries couldn’t be more different! |
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Brazil and South Africa invite comparison because of their many parallels: Continue reading
Show 196 – EVPN Introduction & Use-Cases with Russ White + Jeff Tantsura
This week, Packet Pushers’ hosts Ethan Banks and Greg Ferro queue up a discussion about a new technology, exploring EVPN with Russ White & Jeff Tantsura from Ericsson. What’s EVPN? Well, it’s short for Ethernet VPN, and it’s a way of using BGP as a routing system for MAC addresses. If that sounds like SPB […]
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The post Show 196 – EVPN Introduction & Use-Cases with Russ White + Jeff Tantsura appeared first on Packet Pushers Podcast and was written by Ethan Banks.
EIGRP Query bounding.
In the process of restudying EIGRP as a protocol, and more specifically as to how it converges, you can’t avoid running into the saying “Remember to bound your queries!”.
From a conceptual point of view its fairly easy to understand that the further out you ask for a prefix the longer the convergence process will take. But what really takes place when you have different tools in place to bound the query from taking place?
There are 3 different types of “Query Bounding” techniques that can be utilized:
1) Filters (fx. distribute lists).
2) Summarization
3) Stub routers.
How do they actually work to limit the query scope?
Well, the basic premise for EIGRP queries is the fact that you are asking your fellow EIGRP neighbour for an exact prefix, fx. 172.16.1.0/25. If for any reason you EIGRP neighbour does not have this in his topology table, it will simply respond right away that it doesn’t have a path to this prefix. Query stopped right there.
By using filters such as distribute lists you are removing the prefix from ever getting advertised to the neighbour and as such he will never receive it in his topology Continue reading
Explanation: TunnelX temporarily disabled due to recursive routing
I wanted to take a few minutes to share a scenario that some seem to struggle with. This scenario is a routing issue that sometimes occurs when an interior routing protocol allows routes to leak back through a tunnel. To demonstrate this, I’ve built a lab with three routers. R1 and R3 are participating in EIGRP and have a GRE tunnel configured directly between them.
Topology
Router Configurations
R1
hostname R1 ! interface FastEthernet0/0 ip address 192.168.12.1 255.255.255.0 ! interface Tunnel0 ip address 192.168.13.1 255.255.255.0 tunnel source 192.168.12.1 tunnel destination 192.168.23.3 ! router eigrp 1 network 192.168.0.0 0.0.255.255 ! ip route 0.0.0.0 0.0.0.0 192.168.12.2
R2 (hub)
hostname R2 ! interface FastEthernet0/1 ip address 192.168.12.2 255.255.255.0 ! interface FastEthernet0/1 ip address 192.168.23.2 255.255.255.0 !
R3
hostname R3 ! interface FastEthernet0/1 ip address 192.168.23.3 255.255.255.0 ! interface Tunnel0 ip address 192.168.13.3 255.255.255.0 tunnel source 192.168.23.3 tunnel destination 192.168.12. Continue reading
Cisco IOU – INE v5 R&S Topology
Same Thing Different Version Now with the CCIE Routing and Switching officially on version 5. It’s probably about time that I get back into the game and pick up my numbers. I stopped studying,...[[ Summary content only, you can read everything now, just visit the site for full story ]]
VyOS x64 Installation on Qemu
VyOS is a community fork of Vyatta, a Linux-based network operating system that provides software-based network routing, firewall, and VPN functionality. The VyOS project was started in late 2013 as a community fork of the GPL portions of Vyatta Core 6.6R1 with the goal of maintaining a free and open source network operating system in response to the decision to discontinue the community edition of Vyatta.
VyOS runs on both physical and virtual platforms. It supports paravirtual drivers and integration packages for virtual platforms. It is completely free and open source.
The aim of the tutorial is to show VyOS installation on Qemu virtual machine and get it working on GNS3.
VyOS Qemu and VirtualBox virtual disks can be downloaded here.
I created a Bash script deploy_vyos for automatic deployment of VyOS to Qemu image. The script downloads stable VyOS ISO image from the Internet, creates Qemu disk and starts Qemu virtual machine with attached ISO image. Then is starts Expect script install_vyos that automatically configure all required configuration options without user intervention.
Just copy both scripts to the same directory, assign run privileges to both scripts with the command below and run the deploy_vyos script.
$ chmod +x Continue reading
Confessions of a Troubleshooting Junkie
“Hey Fish, how good are you at BFD? None of my BFD neighbors will come up.” Two simple sentences and I am “hooked.” I love troubleshooting! Troubleshooting is just a blast for me! It’s like being a Network Detective trying to figure out “whodunit” As I sit down in front of the CLI and the […]
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The post Confessions of a Troubleshooting Junkie appeared first on Packet Pushers Podcast and was written by Denise "Fish" Fishburne.
Physical Networks in the Virtualized Networking World
[This post was co-authored by Bruce Davie and Ken Duda]
Almost a year ago, we wrote a first post about our efforts to build virtual networks that span both virtual and physical resources. As we’ve moved beyond the first proofs of concept to customer trials for our combined solution, this post serves to provide an update on where we see the interaction between virtual and physical worlds heading.
Our overall approach to connecting physical and virtual resources can be viewed in two main categories:
- terminating the overlay on physical devices, such as top-of-rack switches, routers, appliances, etc.
- managing interactions between the overlay and the physical devices that provide the underlay.
The latter topic is something we’ve addressed in some other recent posts (here, here and here) — in this blog we’ll focus more on how we deal with physical devices at the edge of the overlay.
We first started working to design a control plane to terminate network virtualization overlays on physical devices in 2012. We started by looking at the information model, defining what information needed to be exchanged between a physical device and a network virtualization controller such as NSX. To bound the problem space, Continue reading
Courage to change things
This was an internal email that I sent to the CloudFlare team about how we are not afraid to throw away old code. We thought it was worth sharing with a wider audience.
Date: Thu, 10 Jul 2014 10:24:21 +0100 Subject: Courage to change things From: John Graham-Cumming To: Everyone Folks, At the Q3 planning meeting I started by making some remarks about how much code we are changing at CloudFlare. I understand that there were audio problems and people may not have heard these clearly, so I'm just going to reiterate them in writing. One of the things that CloudFlare is being brave about is looking at old code and deciding to rewrite it. Lots of companies live with legacy code and build on it and it eventuallybecomes a maintenance nightmare and slows the company down. Over the last year we've made major strides in rewriting parts of our code base so that they are faster, more maintainable, and easier to enhance. There are many parts of the Q3 roadmap that include replacing old parts of our stack. This is incredibly important as it enables us to be more agile and more stable in future. We should feel good Continue reading
Potential Issues with Multicast within a VLAN Spanning Switches
Background
I ran into an interesting issue yesterday at work. There is a new video system
being installed, which takes the video output from computers, encodes it and
sends it as multicast to a controller. The controller then displays it on
a video wall. I had been told that the network has to support multicast.
As all the devices were residing in the same VLAN, I did not expect any issues.
However, the system was not able to receive the multicast. At first we expected
it could be the virtual environment and that the vSwitch did not support multicast,
because one server was deployed on the ESX cluster. The topology was this:
Multicast at Layer 2
Before describing the issue, let’s think about how multicast at layer 2 works.
The source will send to a multicast destination IP. This IP is the converted to a
destination MAC address. If the group is 227.0.0.1, this would map to the MAC
address 0100.5e00.0001. Switches forward multicast and broadcast frames to all
ports in a VLAN. This is not effective in the case of multicast as the traffic
may not have been requested by the host connected to Continue reading
CloudFlare Joins Three More Peering Exchanges in Australia
In the coming weeks, connectivity to CloudFlare in Australia is going to a new level. As part of CloudFlare’s ongoing upgrades program, we established connections to three new Internet exchanges: the Megaport Internet exchanges in Sydney, Brisbane, and Melbourne. These connections doubled the number of Australian Internet exchanges we reach and marked the first exchanges outside of Sydney that Cloudflare participates in.
What is Peering?
When two ISPs peer, they agree to exchange traffic directly between each other rather than sending it a third party. By doing this, both partners avoid congested paths between transit providers, and they avoid paying to ship traffic—it's win-win!
What peering exchanges mean for CloudFlare is that we can significantly increase our service performance to users on ISPs that peer with us. Take Australia for example, for users who are currently on ISPs peering at Megaport, instead of CloudFlare sending traffic to the transit providers of those ISPs, we can now route the traffic directly to them. The result is lower latency, and traffic taking paths that are often less congested.
Low latency is crucial for internet speed due to the nature of TCP, the fundamental protocol on which the internet is built. TCP operates Continue reading
Summary Post – Methods to Manipulate OSPF Costs
There are three ways to manipulate the interface cost in OSPF. One is very direct, one changes the presentation of the interface, and the other changes the calculations for every interface.
Set the cost of the interface directly – Just give it the number you want. Easy. This is the number OSPF will use in the SPF calculations without doing any math on the interface.
R1(config-if)#ip ospf cost 8482
Set the bandwidth of the interface – The formula that OSPF uses to calculate interface cost is pretty easy to remember – (reference bandwidth) / (interface bandwidth). Changing the interface bandwidth will obviously change the result of the calculation. The same caveat for EIGRP route manipulation holds true here; if you change the bandwidth of the interface, you may affect other things like QoS…or EIGRP, now that I mention it.
R1#sh ip ospf inter brief Interface PID Area IP Address/Mask Cost State Nbrs F/C Fa0/0 1 0 192.0.2.1/24 10 DR 0/0 R1#conf t Enter configuration commands, one per line. End with CNTL/Z. R1(config)#int f0/0 R1(config-if)#bandwidth 10 R1(config-if)#do show ip ospf interf brief Interface PID Area IP Address/Mask Cost State Nbrs F/C Fa0/0 1 0 192.0.2.1/24 Continue reading
CCIE RSv5 ATC & Baby 3.0 Status Update
Tomorrow’s CCIE Routing & Switching Advanced Technologies Class v5 is postponed, as baby 3.0’s shipping date has arrived 
Class will tentatively return the week of July 21st, however I will post more information and updates about workbook changes before that.
In the meantime the current CCIE RSv5 ATC streaming playlist can be found here, and the download playlist can be found here. Some videos are still in post processing and will be posted within the next few days.
Although we’re only in week 47 of the class (or so it seems), we’ve put a huge dent in the overall topic scope so far. You can see our current progress in the overall CCIE RSv5 Expanded Blueprint here. Some of topics that haven’t been covered in the v5 ATC officially yet can be found in the CCIE RSv4 ATC and the RSv4 to RSv5 Transition Technologies addendum at the end of that playlist.
RouterOS x86 Qemu and VirtualBox Appliances Download
MikroTik RouterOS is the stand-alone operating system of MikroTik RouterBOARD hardware. It can also be installed on a PC and will turn it into a router with all the necessary features – routing, firewall, bandwidth, management, wireless access point, backhaul link, hotspot, gateway, VPN server and more.
RouterOS x86 installed on Qemu and VirtualBox disks is not licensed, you have 24 hours in total to run these images.
login/pass: admin / password is not set
1. RouterOS x86 6.15
Qemu
https://drive.google.com/file/d/0B6L2h6R5UKMhQUcxMFl2a1pZZGs/edit?usp=sharing
http://sourceforge.net/projects/gns-3/files/Qemu%20Appliances/routeros-6.15-qemu.zip/download
http://www.4shared.com/zip/HG7nubJlba/routeros-615-qemu.html
VirtualBox
https://drive.google.com/file/d/0B6L2h6R5UKMhODYyNm0tWnFjXzA/edit?usp=sharingv
http://sourceforge.net/projects/gns-3/files/VirtualBox%20Appliances/routeros-6.15-vbox.zip/download
http://www.4shared.com/zip/qPN2tmD7ba/routeros-615-vbox.html
SPAN Destination ports and VLAN Membership
Recently at work, a discussion sprouted up around how to handle/configure local session Switched Port Analyzer (SPAN) destination ports. A suggestion was made to create a new VLAN just for these SPAN destination ports and place them there. The justification was that they would be out of VLAN 1, and easily identifiable. Personally I thought it was a waste of a VLAN for a few simple SPAN destination ports, as SPAN destination ports do not participate in spanning tree, and do not forward traffic. However, ultimately in this case it was a good decision due to security requirements.Some key characteristics to know about SPAN destination ports:
- A destination port can be a physical port that is assigned to an EtherChannel group, even if the EtherChannel group has been specified as a SPAN source. The port is removed from the group while it is configured as a SPAN destination port.
- The port does not transmit any traffic except that traffic required for the SPAN session unless learning is enabled.
- The state of the destination port is up/down by design. The interface shows the port in this state in order to make it evident that the port Continue reading