One of the common challenge with almost every routing protocol is SCALABILITY. When it comes to BGP, one of the key requirement under IBGP Specification was to implement Full Mesh. Which is OK most most of Small Enterprises but the solution doesn't scale very well as the Number of IBGP speakers increases. Particularly in Full Mesh Design you need to have n*(n-1)/2 number of peerings which is potentially an Administrative Nightmare.
So couple of solutions were implemented to overcome this issue namely:
> Route-Reflectors(RR)
> Confederations
Technically you can have Route-Reflectors within confederations also but we will not be discussing that or confederations today.
Now one of the potential Scalability issue with Route-Reflector itself is How Many Number of IBGP sessions it can support before it becomes over loaded and we need to introduce another route reflector.
But also part of equation is to figure out if there are any Inbuilt Features into BGP or IOS to help with this scalability problem.
Now in most design or if we follow best practices, the Router Reflector don't need to be/shouldn't be in Traffic Flow Path (Data Plane).
Which means Route Reflector doesn't need to waste it's memory to download BGP routes into its RIB or Routing Table. Which further means avoiding overhead of programming RIB into Hardware and Populate FIB and Going even further if it's a distributed platform and it's using dCEF or something.
So most of the time Number of BGP routes are pretty large in count under most BGP implementations, specially if it's RR and reflecting Internet Routing Table which is about half a million routes these days.
So won't it be cool if we can avoid Route-Reflector to download BGP routes into RIB and just keep it in BGP RIB (BGP Table). As now we can use lots of this extra memory to build more IBGP peerings and scale out.
The answer to this is something called "TABLE MAP" in BGP.
Table Map is a flexible tool which offers many cool features and one among those is to help with problem we just talked about - Stopping BGP Routes from installing in RIB at Route Reflector.
Here is a quick example of how to use this cool feature:
Dahh...
HTH....
Deepak Arora
Evil CCIE
While the World of BGP is keep on changing like any other routing protocol in terms of development, one of the thing that's commonly becoming standard these days or perhaps there is lot of push towards that direction in recent times is adopting the Address Family Structure to keep things neat and clear in terms of configuration review.
Also when it comes to BGP, the configuration lines grow very quickly in Large Enterprise & Data Center environments. And BGP is taking a major place into DMVPN and Large Scale Data Center Environment where Cisco is pushing it under Best Practices in terms of Routing protocol choice.
So one of feature BGP supports to help us with Address Family Structure or it's adoption without creating much pain in butt is - BGP Upgrade CLI.
Here is a quick Example:
HTH...
Deepak Arora
Evil CCIE
Finally it's 1st Jan, 2014. So perhaps just the right time to plan things for 2014 by setting up goals. Of course both personal and professional.
So starting with the interesting part which is CCIE :) , I'll be dedicatedly working on CCIE Data Center Lab Preparation from 1st Of Feb. Yes you read it right, I got to study and finish lots of other topics in the mean while which I would say are requirement of my current project at work.
I had couple of things to choose between initially like :
CCDE - Which is very very interesting as far as learning Design goes. But Designing is just part of my current job as Consultant but lots of other things also have been part of equation as well like Operations, Troubleshooting, Technical Account Management, Planning, Leadership, Helping Customers & Pre-Sales teams with Decision Making, POCs, Documentation etc. But I would more likely return back to CCDE after CCIE DC. Also I would still be trying to spend at least 5 Hrs a week to study Design.
CCIE DC - I had spent couple of months earlier preparing for Storage & Nexus Portion of Lab Blueprint. Also worked quite a bit on Nexus Product line last year including implementing features like VPC, VDC & OTV etc. So possibly will be attempting lab in next 6-9 months.
CCIE SP-OPS - Current Project have lot to do with NGN, ASR Product Line, Unified MPLS Network For Mobile Transport , Network Automation, CGN, EVC etc. I have spent a month time already to learn and grasp this new stuff and will be spending entire Jan too. It's always good to align your job requirements with professional goals. So as I go further with current project, this is something that may push me to go for CCIE SP-OPS. Also Cisco's IOS-XR Specialist certification might be good way to start with.
Also I'll try to find sometime this year to learn some new stuff for which I have developed interests recently like - SDN/Open Flow/One PK, Java Programming, Python Scripting & Basics of Junos, VCP.
Now enough of professional/Career goals. Let's talk about personal goals :)
Lately I have put up lots of weight in last few years. Usually I tell people that I am getting closer in look to Brian M and Scott Morris And More CCIEs means More Weight :)
But I'll find time for Gym now for sure. Also very interested to learn swimming this year.
But on the flip side life is always full of surprises which pushes us further to change or tweak the plans :)
Also I'll try to keep blogging and maintain the difference by talking and writing more about Network Technologies and Products by not following typical or conventional ways but rather keep focusing on making things easier & simple. And maintaining the Fun as part of learning.
With that being said, Happy New Year to All of you from Evil CCIE.
For quite a while I have been trying to understand Hierarchical LSPs uder Cisco New Model developed for Mobile Operators known as Unified MPLS For Mobile Transport (UMMT). In case you haven't noticed, this new model came into picture officially early this year and after certain revisions they reached on version 3 or UMMT 3.0 as final model so far.
The idea behind UMMT is to move away from Traditional flat IP network design that Service Providers have been using for many years. Where they usually run Single IS-IS Level-2 Domain across entire core or Single OSPF Area as well. This design has couple of problems to begin with:
> Single Flat Network Domain Means any small change or instability will cause LSA Flooding or Re-Calculation.
> The network doesn't scale very well as it grows. Eventually large IGP domains means lots of burden on IGP which also further affects our Convergence Requirements from Today's Networks.
> You cannot break network into small pieces/domains as our LSPs requirements are End to End from PE's perspective in order to offer services such as L2/L3 MPLS VPNs & Traffic Engineering etc.
The Idea behind UMMT 3.0 Model is to break the network into multiple domains using different IGP Instances and yet not to compromise on our End To End LSP requirements. So the final picture looks some thing like following:
But as you can below it helps allot with minimizing the routes in every single domains which further helps with Network Convergence requirements of modern networks. Though Network Convergence is a big topic in itself and there are lot of recipes that goes with it in order to achieve the ultimate goal of 50 msec or less convergence time. But I'll focus more on Network Convergence is coming posts.
Although UMMT is a kind of model only, but Cisco is showcasing it's ASR & ME Product line being part of model as follows:
UMMT uses our old friend BGP for creating End to End LSP (Inter Domain) on top of existing LDP based LSPs (Intra Domain). For this they developed something called BGP Labeled Unicast documented under rfc 3107 which to my surprise was written in 2001 :)
With That being said. Here is a Quick Lab Demonstrating how everything fits together and how overall label space will work:
Complete Configuration:
================
R1
##
!
en
!
conf t
!
ho CE-1
!
no ip do lo
!
no cdp run
!
line con 0
no exec-time
logging syn
exit
!
int lo0
ip add 1.1.1.1 255.255.255.255
exit
!
int f0/0
ip add 150.0.0.1 255.255.255.0
no sh
exit
!
router eigrp 100
no auto
net 1.1.1.1 0.0.0.0
net 150.0.0.1 0.0.0.0
exit
!
end
!
++++++++++++++++++++++++++++
R9
##
!
en
!
conf t
!
ho CE-2
!
no ip do lo
!
no cdp run
!
line con 0
no exec-time
logging syn
exit
!
int lo0
ip add 9.9.9.9 255.255.255.255
exit
!
int f0/0
ip add 150.0.0.9 255.255.255.0
no sh
exit
!
router eigrp 100
no auto
net 9.9.9.9 0.0.0.0
net 150.0.0.9 0.0.0.0
exit
!
end
!
++++++++++++++++++++++++++++
R2
##
!
en
!
conf t
!
ho PE-1
!
no ip do lo
!
no cdp run
!
line con 0
no exec-time
logging syn
exit
!
int lo0
ip add 2.2.2.2 255.255.255.255
exit
!
int f1/0
no sh
xconnect 8.8.8.8 1 encapsulation mpls
exit
exit
!
int f1/1
ip add 23.23.23.2 255.255.255.0
mpls ip
no sh
exit
!
mpls label protocol ldp
!
mpls ldp router-id lo0
!
router ospf 1
net 2.2.2.2 0.0.0.0 area 0
net 23.23.23.2 0.0.0.0 area 0
exit
!
router bgp 100
no auto
no sync
net 2.2.2.2 mask 255.255.255.255
nei 4.4.4.4 remote 100
nei 4.4.4.4 update lo0
nei 4.4.4.4 send-label
exit
!
end
!
++++++++++++++++++++++++++++
R3
##
!
en
!
conf t
!
ho P-1
!
no ip do lo
!
no cdp run
!
line con 0
no exec-time
logging syn
exit
!
int lo0
ip add 3.3.3.3 255.255.255.255
exit
!
!
mpls label protocol ldp
!
mpls ldp router-id lo0
!
int f0/0
ip add 23.23.23.3 255.255.255.0
mpls ip
no sh
exit
!
int f0/1
ip add 34.34.34.3 255.255.255.0
mpls ip
no sh
exit
!
router ospf 1
net 0.0.0.0 255.255.255.255 area 0
exit
!
end
!
++++++++++++++++++++++++++++
R4
##
!
en
!
conf t
!
ho RR-1
!
no ip do lo
!
no cdp run
!
line con 0
no exec-time
logging syn
exit
!
int lo0
ip add 4.4.4.4 255.255.255.255
exit
!
!
mpls label protocol ldp
!
mpls ldp router-id lo0
!
int f1/0
ip add 34.34.34.4 255.255.255.0
mpls ip
no sh
exit
!
int f1/1
ip add 45.45.45.4 255.255.255.0
mpls ip
no sh
exit
!
router ospf 2
net 4.4.4.4 0.0.0.0 area 0
net 45.45.45.4 0.0.0.0 area 0
exit
!
ip prefix-list R4Loopback0 seq 5 permit 4.4.4.4/32
!
route-map ospf2-into-ospf1 permit 10
match ip address prefix-list R4Loopback0
exit
!
router ospf 1
net 34.34.34.4 0.0.0.0 area 0
redistribute ospf 2 subnets match internal route-map ospf2-into-ospf1
exit
!
router bgp 100
no auto
no sync
nei 2.2.2.2 remote 100
nei 2.2.2.2 update lo0
nei 2.2.2.2 route-reflector-client
nei 2.2.2.2 next-hop-self all
nei 2.2.2.2 send-label
!
nei 6.6.6.6 remote 100
nei 6.6.6.6 update lo0
nei 6.6.6.6 route-reflector-client
nei 6.6.6.6 next-hop-self all
nei 6.6.6.6 send-label
exit
!
end
!
++++++++++++++++++++++++++++
R5
##
!
en
!
conf t
!
ho P-2
!
no ip do lo
!
no cdp run
!
line con 0
no exec-time
logging syn
exit
!
int lo0
ip add 5.5.5.5 255.255.255.255
exit
!
!
mpls label protocol ldp
!
mpls ldp router-id lo0
!
int f0/0
ip add 45.45.45.5 255.255.255.0
mpls ip
no sh
exit
!
int f0/1
ip add 56.56.56.5 255.255.255.0
mpls ip
no sh
exit
!
router ospf 2
net 0.0.0.0 255.255.255.255 area 0
exit
!
end
!
++++++++++++++++++++++++++++
R6
##
!
en
!
conf t
!
ho RR-2
!
no ip do lo
!
no cdp run
!
line con 0
no exec-time
logging syn
exit
!
int lo0
ip add 6.6.6.6 255.255.255.255
exit
!
!
mpls label protocol ldp
!
mpls ldp router-id lo0
!
int f1/1
ip add 56.56.56.6 255.255.255.0
mpls ip
no sh
exit
!
int f1/0
ip add 76.76.76.6 255.255.255.0
mpls ip
no sh
exit
!
!
router ospf 2
net 6.6.6.6 0.0.0.0 area 0
net 56.56.56.6 0.0.0.0 area 0
exit
!
ip prefix-list R6Loopback0 seq 5 permit 6.6.6.6/32
!
route-map ospf2-into-ospf3 permit 10
match ip address prefix-list R6Loopback0
exit
!
router ospf 3
net 76.76.76.6 0.0.0.0 area 0
redistribute ospf 2 subnets match internal route-map ospf2-into-ospf3
exit
!
router bgp 100
no auto
no sync
nei 4.4.4.4 remote 100
nei 4.4.4.4 update lo0
nei 4.4.4.4 route-reflector-client
nei 4.4.4.4 next-hop-self all
nei 4.4.4.4 send-label
!
nei 8.8.8.8 remote 100
nei 8.8.8.8 update lo0
nei 8.8.8.8 route-reflector-client
nei 8.8.8.8 next-hop-self all
nei 8.8.8.8 send-label
exit
!
end
!
++++++++++++++++++++++++++++
R7
##
!
en
!
conf t
!
ho P-3
!
no ip do lo
!
no cdp run
!
line con 0
no exec-time
logging syn
exit
!
int lo0
ip add 7.7.7.7 255.255.255.255
exit
!
!
mpls label protocol ldp
!
mpls ldp router-id lo0
!
int f0/1
ip add 76.76.76.7 255.255.255.0
mpls ip
no sh
exit
!
int f0/0
ip add 87.87.87.7 255.255.255.0
mpls ip
no sh
exit
!
router ospf 3
net 0.0.0.0 255.255.255.255 area 0
exit
!
end
!
++++++++++++++++++++++++++++
R8
##
!
en
!
conf t
!
ho PE-2
!
no ip do lo
!
no cdp run
!
line con 0
no exec-time
logging syn
exit
!
int lo0
ip add 8.8.8.8 255.255.255.255
exit
!
!
mpls label protocol ldp
!
mpls ldp router-id lo0
!
int f1/1
ip add 87.87.87.8 255.255.255.0
mpls ip
no sh
exit
!
int f1/0
no sh
xconnect 2.2.2.2 1 encapsulation mpls
exit
exit
!
router ospf 3
net 8.8.8.8 0.0.0.0 area 0
net 87.87.87.8 0.0.0.0 area 0
exit
!
router bgp 100
no auto
no sync
net 8.8.8.8 mask 255.255.255.255
nei 6.6.6.6 remote 100
nei 6.6.6.6 update lo0
nei 6.6.6.6 send-label
exit
!
end
!
+++++++++++++++++++++++++++++
Label Space & Verification
=================
PE-1#sh mpls forwarding-table
Local Outgoing Prefix Bytes Label Outgoing Next Hop
Label Label or Tunnel Id Switched interface
16 Pop Label 3.3.3.3/32 0 Fa1/1 23.23.23.3
17 Pop Label 34.34.34.0/24 0 Fa1/1 23.23.23.3
18 17 4.4.4.4/32 0 Fa1/1 23.23.23.3
19 No Label l2ckt(1) 29118 Fa1/0 point2point
PE-1#sh ip route 8.8.8.8
Routing entry for 8.8.8.8/32
Known via "bgp 100", distance 200, metric 0, type internal
Last update from 4.4.4.4 00:39:45 ago
Routing Descriptor Blocks:
* 4.4.4.4, from 4.4.4.4, 00:39:45 ago
Route metric is 0, traffic share count is 1
AS Hops 0
MPLS label: 22
PE-1#sh ip cef 8.8.8.8
8.8.8.8/32
nexthop 23.23.23.3 FastEthernet1/1 label 17 22
PE-1#sh ip cef 8.8.8.8 detail
8.8.8.8/32, epoch 0, flags rib defined all labels
1 RR source [no flags]
recursive via 4.4.4.4 label 22
nexthop 23.23.23.3 FastEthernet1/1 label 17
PE-1#sh bgp ipv4 unicast labels
Network Next Hop In label/Out label
2.2.2.2/32 0.0.0.0 imp-null/nolabel
8.8.8.8/32 4.4.4.4 nolabel/22
P-1#sh mpls forwarding-table
Local Outgoing Prefix Bytes tag Outgoing Next Hop
tag tag or VC or Tunnel Id switched interface
16 Pop tag 2.2.2.2/32 60043 Fa0/0 23.23.23.2
17 Pop tag 4.4.4.4/32 63026 Fa0/1 34.34.34.4
P-1#sh mpls forwarding-table labels 17 detail
Local Outgoing Prefix Bytes tag Outgoing Next Hop
tag tag or VC or Tunnel Id switched interface
17 Pop tag 4.4.4.4/32 111825 Fa0/1 34.34.34.4
MAC/Encaps=14/14, MRU=1504, Tag Stack{}
CA0C17A0001CC20B1B2000018847
No output feature configured
Per-packet load-sharing
RR-1#sh mpls forwarding-table
Local Outgoing Prefix Bytes Label Outgoing Next Hop
Label Label or Tunnel Id Switched interface
16 Pop Label 3.3.3.3/32 0 Fa1/0 34.34.34.3
17 16 2.2.2.2/32 57654 Fa1/0 34.34.34.3
18 Pop Label 23.23.23.0/24 0 Fa1/0 34.34.34.3
19 Pop Label 5.5.5.5/32 0 Fa1/1 45.45.45.5
20 Pop Label 56.56.56.0/24 0 Fa1/1 45.45.45.5
21 17 6.6.6.6/32 0 Fa1/1 45.45.45.5
22 21 8.8.8.8/32 60902 Fa1/1 45.45.45.5
RR-1#sh mpls forwarding-table labels 22 detail
Local Outgoing Prefix Bytes Label Outgoing Next Hop
Label Label or Tunnel Id Switched interface
22 21 8.8.8.8/32 111502 Fa1/1 45.45.45.5
MAC/Encaps=14/22, MRU=1496, Label Stack{17 21}
C20D1B200000CA0C17A0001D8847 0001100000015000
No output feature configured
RR-1#sh bgp ipv4 unicast labels
Network Next Hop In label/Out label
2.2.2.2/32 2.2.2.2 17/imp-null
8.8.8.8/32 6.6.6.6 22/21
P-2#sh mpls forwarding-table
Local Outgoing Prefix Bytes tag Outgoing Next Hop
tag tag or VC or Tunnel Id switched interface
16 Pop tag 4.4.4.4/32 63393 Fa0/0 45.45.45.4
17 Pop tag 6.6.6.6/32 63803 Fa0/1 56.56.56.6
P-2#sh mpls forwarding-table labels 16 detail
Local Outgoing Prefix Bytes tag Outgoing Next Hop
tag tag or VC or Tunnel Id switched interface
16 Pop tag 4.4.4.4/32 124541 Fa0/0 45.45.45.4
MAC/Encaps=14/14, MRU=1504, Tag Stack{}
CA0C17A0001DC20D1B2000008847
No output feature configured
Per-packet load-sharing
P-2#sh mpls forwarding-table labels 17 detail
Local Outgoing Prefix Bytes tag Outgoing Next Hop
tag tag or VC or Tunnel Id switched interface
17 Pop tag 6.6.6.6/32 125808 Fa0/1 56.56.56.6
MAC/Encaps=14/14, MRU=1504, Tag Stack{}
CA0E04F4001DC20D1B2000018847
No output feature configured
Per-packet load-sharing
RR-2#sh mpls forwarding-table
Local Outgoing Prefix Bytes Label Outgoing Next Hop
Label Label or Tunnel Id Switched interface
16 Pop Label 5.5.5.5/32 0 Fa1/1 56.56.56.5
17 16 4.4.4.4/32 0 Fa1/1 56.56.56.5
18 Pop Label 45.45.45.0/24 0 Fa1/1 56.56.56.5
19 Pop Label 7.7.7.7/32 0 Fa1/0 76.76.76.7
20 Pop Label 87.87.87.0/24 0 Fa1/0 76.76.76.7
21 17 8.8.8.8/32 60618 Fa1/0 76.76.76.7
22 17 2.2.2.2/32 62592 Fa1/1 56.56.56.5
RR-2#show mpls forwarding-table labels 21 detail
Local Outgoing Prefix Bytes Label Outgoing Next Hop
Label Label or Tunnel Id Switched interface
21 17 8.8.8.8/32 124158 Fa1/0 76.76.76.7
MAC/Encaps=14/18, MRU=1500, Label Stack{17}
C20F1B200001CA0E04F4001C8847 00011000
No output feature configured
RR-2#sh bgp ipv4 unicast labels
Network Next Hop In label/Out label
2.2.2.2/32 4.4.4.4 22/17
8.8.8.8/32 8.8.8.8 21/imp-null
P-3#sh mpls forwarding-table
Local Outgoing Prefix Bytes tag Outgoing Next Hop
tag tag or VC or Tunnel Id switched interface
16 Pop tag 6.6.6.6/32 64910 Fa0/1 76.76.76.6
17 Pop tag 8.8.8.8/32 62636 Fa0/0 87.87.87.8
P-3#sh mpls forwarding-table labels 17 detail
Local Outgoing Prefix Bytes tag Outgoing Next Hop
tag tag or VC or Tunnel Id switched interface
17 Pop tag 8.8.8.8/32 134673 Fa0/0 87.87.87.8
MAC/Encaps=14/14, MRU=1504, Tag Stack{}
CA101C74001DC20F1B2000008847
No output feature configured
Per-packet load-sharing
PE-2#sh mpls forwarding-table
Local Outgoing Prefix Bytes Label Outgoing Next Hop
Label Label or Tunnel Id Switched interface
16 Pop Label 7.7.7.7/32 0 Fa1/1 87.87.87.7
17 Pop Label 76.76.76.0/24 0 Fa1/1 87.87.87.7
18 16 6.6.6.6/32 0 Fa1/1 87.87.87.7
19 No Label l2ckt(1) 32252 Fa1/0 point2point
PE-1#traceroute 8.8.8.8 source loopback 0
Type escape sequence to abort.
Tracing the route to 8.8.8.8
VRF info: (vrf in name/id, vrf out name/id)
1 23.23.23.3 [MPLS: Labels 17/22 Exp 0] 1052 msec 1084 msec 440 msec
2 34.34.34.4 [MPLS: Label 22 Exp 0] 612 msec 1416 msec 1324 msec
3 45.45.45.5 [MPLS: Labels 17/21 Exp 0] 864 msec 972 msec 604 msec
4 56.56.56.6 [MPLS: Label 21 Exp 0] 644 msec 1376 msec 1292 msec
5 *
76.76.76.7 [MPLS: Label 17 Exp 0] 1136 msec 832 msec
6 87.87.87.8 1752 msec 1524 msec 1464 msec
CE-1#traceroute 9.9.9.9 source loopback 0
Type escape sequence to abort.
Tracing the route to 9.9.9.9
1 150.0.0.9 1480 msec 1100 msec 880 msec
P-1#sh ip route 8.8.8.8
% Network not in table
+++++++++++++++++++++++++++++++++++++++++
Stay Tuned For Next Part Of Series as we will dig the UMMT deeper :)
HTH...
Deepak Arora
Evil CCIE
