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- About filopeter
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Member since
09-12-2014
60
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40
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7
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04-04-2020
01:41 PM
Here are my comments to your questions My BGP neighbors are not discovered by static routing but via the connected interfaces. If my BGP neighbors were configured via loopbacks and static routes would MPLS tagging have been used by default? LDP protocol assigns labels to all IGP learned prefixes, including the static routes. Cisco IOS does not assign labels to BGP learned prefixes, until you configure the "send-label" command. Also one more question please if I may. On one router when configuring I enabled MPLS before I had configured the label range. I fixed this by rebooting the router afterwards and the labels I wanted were then in effect. Is there any command I can use to do this without rebooting? Label range change requires a reboot.
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04-04-2020
01:40 PM
There are MPLS based Data Center network designs, where only eBGP is used in the control plane. eBGP is also used to advertise labels and so it completely replaces the LDP. This simplifies the DC control plane, because IGP or LDP are not more required. Every multilayer switch in the DC spine-leaf architecture has its own BGP AS and communicates with other nodes using eBGP protocol. This approach is the base for overlay services, like VPLS in the DC.
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04-01-2020
09:10 AM
It is not usual to have such setup as you are using. Cisco IOS by default does not assign labels to IPv4 prefixes learned by BGP. To overcome this behavior you need to configure the following command under bgp process on your eBGP peers ! router bgp 65404 neighbor 172.20.40.3 remote-as 65403 neighbor 172.20.40.3 send-label ! I hope this helps, P.
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03-06-2020
12:28 AM
There is a nice document which describes loop-prevention techniques when running ospf on ce-pe link. https://www.cisco.com/c/en/us/support/docs/ip/open-shortest-path-first-ospf/118800-configure-ospf-00.html In this document you can find the following note: MPLS VPN OSPF PE-CE always includes the loop-prevention mechanism in order to handle issues. In the older Cisco IOS, the Per original IETF draft Type 3 LSAs use the DN Bit in LSA and Type 5 LSAs use a tag. The newer RFC 4576 mandates use of DN Bit for both Type 3 and Type 5 LSAs. This was committed via Cisco bug ID CSCtw79182. The PE routers with Cisco IOS images with the fix of this defect will originate Type 5 external LSAs with both DN Bit and a tag as loop-prevention mechanisms. Previous Cisco IOS versions advertised the only tag for this purpose for External Routes. I hope this helps, P.
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03-04-2020
03:36 AM
2) To avoid redistribution of connected subnets is generally true for pure IP environment and IGP routing protocols. But In MPLS VPN environment you have to deal either with redistribution to MP-BGP, or you have to run eBGP on CE-PE interfaces. Redistribution of connected subnets to BGP is common practice.
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03-04-2020
12:17 AM
1/ OSPF treats Loopback interfaces as stub networks and advertise them as host routes (with mask /32) regardless of their configured/native mask. To change this default behaviour you have to configure the OSPF network type to point-to-point network. The best practice is to use /32 masks for loopback interfaces. 2/ In MPLS VPNs you usually also advertise the subnet between PE and CE routers (in your case 192.168.1.0/24 or 192.168.10.0/24 in vrf Customer 1). You can do this in two ways - advertise this network under eigrp and then redistribute eigrp to bgp like you did - redistribute connected subnets to bgp, as these networks are directly connected to your PEs 3/ do not forget to increase the MTU on mpls enabled interfaces to avoid possible fragmentation
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03-03-2020
07:53 AM
It looks like you have an broken LSP. Configure "ip ospf network point-to-point" under your Loopback 0 interfaces on PE-LER and PE-LER-1. In case of OSPF as IGP, this command is required to advertise the real netmask of your loopback interface. If the loopback's real netmask is not /32 (in your case it is /24), you have a disparity between the information advertised by OSPF and LDP. While LDP advertises the true loopback's address/netmask and label mapping, the receiving LSR does not recognizes this label mapping because it does not know the address/netmask in its routing table, as OSPF advertises the loopback using the /32 netmask by default. In the provided output you see also "no label" instead of "pop label" for 3.3.3.3/32
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03-03-2020
03:54 AM
You have mentioned that the ping on loopbacks does not work. Do you mean ping between LER routers (3.3.3.3 and 8.8.8.8), or ping between CE routers (1.1.1.0/24 and 9.9.9.0/24)? Routing exchange is control plane task and forwarding of packets is data plane task. Sometimes you may have issue only in the MPLS data plane, like broken LSP path (for example "mpls ip" is not configured between LSR routers in your drawing).
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03-03-2020
12:40 AM
Hello, try to turn off eigrp auto-summary on PE-LER1: ! router eigrp 1 auto-summary ! address-family ipv4 vrf Customer1 redistribute bgp 100 metric 64 1000 255 1 1500 network 8.8.8.0 0.0.0.255 network 192.168.10.0 auto-summary autonomous-system 1 exit-address-family ! Best Regards, P.
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02-26-2020
07:53 AM
Hello, check also your ip mtu on interface Vlan1617 - "show ip interface vlan1617". If necessary try to configure higher MTU using ip mtu command under interface vlan 1617, or try to increase the MTU in the vlan config mode ! Switch(config)# vlan 1617 Switch(config-vlan)# mtu 1600 ! Best Regards, P.
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Created by
filopeter
in IP Telephony and Phones
in IP Telephony and Phones
11-22-2019
02:19 AM
11-22-2019
02:19 AM
Hello, they are ip phones from vendors like Linksys which support cdp protocol and can learn voice vlan and other parameters over cdp. Do you know if the conditional trust can be applied to these ip phones? Is the conditional trust based on some flags inside the cdp protocol, or there is a database of supported vendors/ip phone models inside ios? Best Regards, P.
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Labels:
11-07-2019
06:30 AM
Under pseudowire redundancy I mean the following configuration on ASR901 interface GigabitEthernet0/0/1 no ip address ! service instance 12 ethernet encapsulation dot1q 12 rewrite ingress tag pop 1 symmetric xconnect 172.16.0.14 3333 encapsulation mpls backup peer 172.16.0.13 3333 If the primary PW goes down, the ASR 901 diverts traffic to the backup PW.
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11-06-2019
12:55 AM
Hello, afaik the ASR901 does not support VPLS, just EoMPLS. You can you pseudowire redundancy to achieve high availability. What kind of P routers do you use in your topology? Could you please provide some part of the configuration? Best Regards, P.
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10-24-2019
02:36 PM
Hello, could someone please explain which packets/frames belong to groups in the third column (NAME) of the following command Switch#show platform hardware fed switch active fwd-asic drops exceptions It would be also useful to know if the output is in frames or bytes Here is the output
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Labels:
10-23-2019
01:23 AM
To override the default OSPF behavior on CE-PE interface, you can either manually configure domain-tag on PE1 to a different value, or configure capability vrf-lite on PE2, which ignores the DN bit/domain-id. Please consider possible routing loops which may happen after these changes.
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04-04-2020
Here are my comments to your questionsMy BGP neighbors are not
discovered by static routing but via ...
04-04-2020
There are MPLS based Data Center network designs, where only eBGP is
used in the control plane. eBGP...
04-01-2020
It is not usual to have such setup as you are using.Cisco IOS by default
does not assign labels to I...
03-06-2020
There is a nice document which describes loop-prevention techniques when
running ospf on ce-pe link....
03-04-2020
2) To avoid redistribution of connected subnets is generally true for
pure IP environment and IGP ro...
03-04-2020
1/ OSPF treats Loopback interfaces as stub networks and advertise them
as host routes (with mask /32...
03-03-2020
It looks like you have an broken LSP. Configure "ip ospf network
point-to-point" under your Loopback...
03-03-2020
You have mentioned that the ping on loopbacks does not work. Do you mean
ping between LER routers (3...
03-03-2020
Hello,try to turn off eigrp auto-summary on PE-LER1:!router eigrp
1auto-summary!address-family ipv4 ...
02-26-2020
Hello,check also your ip mtu on interface Vlan1617 - "show ip interface
vlan1617".If necessary try t...
Created by
filopeter
in IP Telephony and Phones
11-22-2019
11-22-2019
Hello,they are ip phones from vendors like Linksys which support cdp
protocol and can learn voice vl...
11-07-2019
Under pseudowire redundancy I mean the following configuration on
ASR901interface GigabitEthernet0/0...
11-06-2019
Hello,afaik the ASR901 does not support VPLS, just EoMPLS. You can you
pseudowire redundancy to achi...
10-24-2019
Hello,could someone please explain which packets/frames belong to groups
in the third column (NAME) ...
Public Statistics
| Date Registered | 09-12-2014 12:11 AM |
| Date Last Visited | 04-08-2020 12:57 AM |
| Total Messages Posted | 60 |
| Total Helpful Votes Received | 40 |
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