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<div>With regards to IGP convergence issues I believe there is no big difference between OSPF and IS-IS if I am not wrong. My 1+ for IS-IS if you have multiple routed protocol I.e. IPv4 and IPv6 etc. </div>
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<div>In SP network convergence issues are mostly handled in design level I.e. de-coupling IGP and EGP. I.e Only loopback and p2p link in OSPF/ISIS. So if there is any topology change in IGP, packet loss probability is very very less. </div>
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<div>For external prefixes like downstream customer and upstream Internet, people mostly use eBGP. Across the infrastructure iBGP. Convergence time is an issue here specially if you have full BGP feed from multiple upstream. Try using vendor specific tools
like BFD, BGP scanner etc. Or full BGP feed from single upstream and default from other etc. What else? :)</div>
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<div>Regards</div>
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<div>Roman </div>
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<span style="font-weight:bold">From: </span>"Md. Faridul Alam | Aamra" <<a href="mailto:faridul.alam@aamra.com.bd">faridul.alam@aamra.com.bd</a>><br>
<span style="font-weight:bold">Date: </span>Monday, 18 November 2013 5:49 AM<br>
<span style="font-weight:bold">To: </span>"'Simon Sohel Baroi / IIG-ITC / Sr.Manager / 01678618243 /'" <<a href="mailto:simon.baroi@fiberathome.net">simon.baroi@fiberathome.net</a>>, "<a href="mailto:nog@bdnog.org">nog@bdnog.org</a>" <<a href="mailto:nog@bdnog.org">nog@bdnog.org</a>><br>
<span style="font-weight:bold">Subject: </span>Re: [bdNOG] ISIS of OSPF<br>
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<p class="MsoNormal"><span style="font-size: 11pt; font-family: Calibri, sans-serif; ">I prefer IS-IS over OSPF for below reasons:<o:p></o:p></span></p>
<p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l0 level1 lfo1"><!--[if !supportLists]--><span style="font-size:11.0pt;font-family:"Calibri","sans-serif""><span style="mso-list:Ignore">1.<span style="font-style: normal; font-variant: normal; font-weight: normal; font-size: 7pt; line-height: normal; font-family: 'Times New Roman'; ">
</span></span></span><!--[endif]--><span style="font-size: 11pt; font-family: Calibri, sans-serif; ">Security<o:p></o:p></span></p>
<p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l0 level1 lfo1"><!--[if !supportLists]--><span style="font-size:11.0pt;font-family:"Calibri","sans-serif""><span style="mso-list:Ignore">2.<span style="font-style: normal; font-variant: normal; font-weight: normal; font-size: 7pt; line-height: normal; font-family: 'Times New Roman'; ">
</span></span></span><!--[endif]--><span style="font-size: 11pt; font-family: Calibri, sans-serif; ">Modularity<o:p></o:p></span></p>
<p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l0 level1 lfo1"><!--[if !supportLists]--><span style="font-size:11.0pt;font-family:"Calibri","sans-serif""><span style="mso-list:Ignore">3.<span style="font-style: normal; font-variant: normal; font-weight: normal; font-size: 7pt; line-height: normal; font-family: 'Times New Roman'; ">
</span></span></span><!--[endif]--><span style="font-size: 11pt; font-family: Calibri, sans-serif; ">Overload Mechanism<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family: Calibri, sans-serif; ">Also, I prefer IS-IS over OSPF because we can design a large networks by building a single large Level 1 (L1) area without any hierarchies in IS-IS and still be able to manage,
something that would be difficult with OSPF. There are issues with inter-area traffic engineering and such and most people would like to keep their network as a single area if the routing protocol can manage it.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family: Calibri, sans-serif; "><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family: Calibri, sans-serif; ">There are some restrictions for applications like MPLS TE that require flat area 0 for OSPF or flat level 2 for IS-IS. This also simplifies the design so heirarchy isn't
an issue. But maintaining large number of LSA�s in a single area is very difficult for OSPF. So IS-IS is better for MPLS.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(0, 32, 96); "><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(0, 32, 96); "><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(0, 0, 204); ">Regards,
</span><span style="font-size: 10pt; font-family: Tahoma, sans-serif; color: rgb(0, 112, 192); ">Farid</span><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(0, 32, 96); "><o:p></o:p></span></p>
<p class="MsoNormal"><b><span style="font-size: 9pt; font-family: Tahoma, sans-serif; color: red; ">Aamra</span></b><span style="font-size: 9pt; font-family: Tahoma, sans-serif; color: red; ">,</span><i><span style="font-size: 8pt; font-family: Tahoma, sans-serif; color: rgb(38, 38, 38); ">
the power of WE</span></i><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); "><o:p></o:p></span></p>
<p class="MsoNormal"><b><span style="font-size: 10pt; font-family: Tahoma, sans-serif; ">From:</span></b><span style="font-size: 10pt; font-family: Tahoma, sans-serif; ">
<a href="mailto:nog-bounces@bdnog.org">nog-bounces@bdnog.org</a> [<a href="mailto:nog-bounces@bdnog.org">mailto:nog-bounces@bdnog.org</a>]
<b>On Behalf Of </b>Simon Sohel Baroi / IIG-ITC / Sr.Manager / 01678618243 /<br>
<b>Sent:</b> 18-Nov-2013 12:08 AM<br>
<b>To:</b> <a href="mailto:nog@bdnog.org">nog@bdnog.org</a><br>
<b>Subject:</b> [bdNOG] ISIS of OSPF<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal" style="margin-bottom:12.0pt">Dare All the bdNOG friends,<br>
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Which one is better ISIS or OSPF.<o:p></o:p></p>
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<p class="MsoNormal" style="margin-bottom:12.0pt">I'm mainly focusing of fast convergence time. My clients can not give me any ping loss in that convergence moment, if one fiber goes down in my MPLS link.<o:p></o:p></p>
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<p class="MsoNormal" style="margin-bottom:12.0pt">Number of router will be around 600.<o:p></o:p></p>
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<p class="MsoNormal" style="margin-bottom:12.0pt">Need your help guys.<o:p></o:p></p>
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<p class="MsoNormal">- SIMON<br>
Fiber@Home.<o:p></o:p></p>
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<p class="MsoNormal"><br>
-- <br>
<b><span style="font-size: 7.5pt; font-family: Tahoma, sans-serif; ">Simon Sohel Baroi
</span></b><span style="font-size: 7.5pt; font-family: Tahoma, sans-serif; ">| Sr. Manager, Technology | PICO | ITC -
</span><span style="font-size: 10pt; font-family: Tahoma, sans-serif; ">IIG |</span><span style="font-size: 7.5pt; font-family: Tahoma, sans-serif; "><br>
Cell : +880-1678-618243, +880-181-7022207 | Desk : +880-9666776677 Ext-1031 | </span><o:p></o:p></p>
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<p class="MsoNormal" style="margin-bottom:12.0pt"><span style="font-size: 7.5pt; font-family: Tahoma, sans-serif; ">Mail :
<a href="mailto:simon.baroi@fiberathome.net" target="_blank">simon.baroi@pico.net.bd</a> | Skype : tx.fttx |<span style="color:#006600"><o:p></o:p></span></span></p>
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<p class="MsoNormal"><b><i><span style="font-size: 7.5pt; font-family: Tahoma, sans-serif; color: rgb(0, 102, 0); ">Reduce. Reuse. Recycle. Respect. It's the little things that really can make a difference.</span></i></b><span style="font-size: 7.5pt; font-family: Tahoma, sans-serif; color: rgb(0, 102, 0); "><o:p></o:p></span></p>
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