Questions tagged [bgp]

BGP is Border Gateway Protocol, used on the internet both inside of and in between networks.

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2answers
168 views

Global BGP Routing only by only importing supernet prefixes

I was wondering if global IPv4 Routing can be technically achieved only by importing from the ISP Provider (providing us with a IPv4 BGP full table) a subset from the BGPv4 routes (i.e. all prefixes ...
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10 views

Packet Clearing House RIB Dumps

I want to use PCH collectors RIB Dumps as another source of information for a project, while I already use Routeviews and RIPE ris. I want to collect the RIBs that are created at 08:00 UTC. This is ...
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1answer
19 views

In case if BGP connected to two peers then how Graceful restart capability advertised in open message

As per RFC 4724 "A BGP speaker MUST NOT include more than one instance of the Graceful Restart Capability in the capability advertisement [BGP-CAP]. If more than one instance of the Graceful ...
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47 views

can some one explain BGP router graceful restart flow?

can some one please explain BGP router graceful restart flow , how the messages will exchange before restart and after session re-establish between BGP router and it's peer.
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1answer
41 views

Understanding MP-BGP IPv4 AFI

I was writing my own BGP speaker, and I am a bit confused by the IPv4 AFI of MP-BGP. I understand that to exchange IPv6 routing information peers need to agree on it by sending the MP-BGP capability ...
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34 views

Why is bgp used for AWS and gcp VPNs and not another routing protocol? [closed]

I use AWS and gcp. Both of these cloud platforms have the ability to establish a VPN connection from a VPC in the cloud to an on-premise router or another cloud VPN endpoint. They both use bgp ( and ...
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1answer
23 views

bgp filtering based on conjunction of prefix-list and as-path originator

Is there any way of having a filter that uses as-path origin and prefix-list together. For example I want to accept updates from origin of AS 5745 and prefix-list is say 189.150.20.X/24. Any other ...
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1answer
27 views

What is the use of route-target without export/import?

On my router, I can configure the following: I canont find any information regarding the use of the "route-target ASN:nn" command. I know what route-target import/export allows me to do, but what use ...
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1answer
56 views

Regarding Administrative Distance

Different vendors use different Administrative distance for the same protocol.For example, in a Cisco router, the eBGP, AD value is 20, whereas in Arista routers, it appears different(i believe, 200). ...
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2answers
875 views

Does anycast addressing add additional latency in any way?

Does anycast addressing, in itself, add any additional latency to network connections? Specifically, if you had two servers located in the same data center that had extremely similar routes/number of ...
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1answer
61 views

BGP | Advertise a summary prefix out to customer location

I don't know what I should be using for this or how I should go about it. In my lab where I am testing out the BGP configs that I've learned I want my ISP topology to have a summary prefix for the ...
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0answers
52 views

Route Reflector not reflecting BGP-LU (Labelled Unicast) prefixes

I was reading about the Inter-AS MPLS VPN Option C from book ' MPLS in the SDN Era' . In it , the author establishes the BGP-LU peering between PEs and ASBRs and between RR and ASBR only.No BGP-LU ...
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1answer
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Whether the anycast nodes can not in the same AS, and whether the different AS can pronounce the same IP segment?

The Anycast realize is through annunciate the same IP address in the different node using BGP protocol. you see the Server A and Server B use the BGP annunciate the same IP address 10.0.0.1. There ...
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2answers
99 views

BGP multi-path using loopback

I have above scenario where i have multiple PATH for my BGP so i have to setup loopback interface to make it ECMP routing on both path. I have cisco nexus switches and following is my first router ...
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1answer
78 views

How does IP assignment work for servers and data centers

If I had an IP address (for example bought range for my company), and 2 ISPs fibres, how would it be possible to set my network card to have same IP adress accessible from both connections? (know its ...
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2answers
824 views

BGP convergence issue

I have 2 different carriers on my Cisco 2921 router and I have set weight to 350 for my first carrier to force it for my outbound traffic, and I set second carrier weight to 300. I am receiving BGP ...
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2answers
100 views

Regarding eBGP Multipath

In one of the blogs, i read: "Unlike most routing protocols, BGP only selects a single best path for each prefix. It doesn’t do ECMP (Equal Cost Multi-Path Routing) by default but it is possible to ...
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0answers
31 views

How to get traffic to take BGP route if not matched in PBR?

I am a newbie to BGP and have an ASR1001x router (172.16.0.3), I'm forwarding an ACL to a second router (172.16.0.1) while I try to get BGP working on this one for a specific testing prefix-list ...
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2answers
68 views

Hub-Spoke communication with BGP

I'm trying to establish connectivity between Hub and Spoke locations of same enterprise with same AS using BGP. Within DC (hub) iBGP and OSPF is used and eBGP is established between Spokes and MPLS ...
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2answers
142 views

No route to host for IPs in same subnet being routed by bgp

I have set up BGP to do some custom routing for a subset of addresses in the range 192.168.1.0/24. I have verified that the BGP is working by testing ping/curl on a different host in a different ...
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2answers
115 views

Running iBGP without IGP

Given following setup: Configuration of the routers is very straight forward. Router BGP1: interface Loopback0 ip address 1.1.1.1 255.255.255.255 ! interface Loopback9 ip address 9.9.9.9 255.255....
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1answer
43 views

VPLS how to signal CE facing interface failure

Hello, I have a BGP-based VPLS setup with one CE machine being multi-homed multi-homing works if i for example shut the active PE or i somehow disturb the connection between my PEs... that ok but ...
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21 views

How to force client side HSRP interface to go into standby when internet is not reachable [duplicate]

I have a VIRL setup in which the client router is connected to a client switch that connected to two provider switches that have HSRP configured for the client gateway. The two switches are in an OSPF ...
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1answer
36 views

H-VPLS application with different types of VPLS

so ive been digging around VPLS for a while and i have come across a term H-VPLS. My knowledge is: VPLS can be signalled using LDP (manual or autodiscovery) or BGP (autodiscovery). H-VPLS: ...
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1answer
89 views

How to change AD on Juniper router?

I have this route on my Juniper Router and some destinations have two routes: OSPF and BGP. I want to change the administrative distance for the BGP route so that it will be smaller than the OSPF ...
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1answer
71 views

How to explain that a route has two different AS numbers?

I have a question about the AS path, see the below example where I show the route 114.114.114.114. This shows several BGP routes. See the fist route item. The AS path is 4809 4134 I, I want to know ...
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1answer
62 views

Can not use `update-source` in bgp neighbor command in Cisco Packet Tracer

In my Cisco Packet Tracer, I have a ISR4321 router: Router1(config-router)#neighbor 12.0.0.2 update-source lo0 ^ % Invalid input detected at '^' marker. I ...
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1answer
162 views

What's the meaning of `State` and `PfxRcd`?

When I execute the show ip bgp summary, I get the bellow data: Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd 12.0.0.2 4 200 199 190 12 0 ...
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1answer
301 views

What's the commands of Cisco query bgp neighbor table, bgp table and router table?

In the AS router, I want to query its bgp neighbor table, bgp table, and router table. what's the commands of them?
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3answers
297 views

Why the last AS PATH item always is `I` or `?`? [duplicate]

you see my snapshot from m Juniper Router, I want to find the routes of 114.114.114.114, but there always get Idle or a ?, why:
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3answers
112 views

Why do all the intermediary routers need to run iBGP without tunneling?

I'm trying to understand the configuration behind iBGP - I understand you can run full mesh to prevent loops, run confederation or route reflectors, if you don't want full mesh, else run tunneling ...
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1answer
197 views

What does “Allow AS in” do in BGP?

When configure BGP in a SDN product, i saw there is an option to enable "Allow as in", could anyone know what is it!
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87 views

What's the meaning of `%BGP-3-NOTIFICATION: sent to neighbor 12.0.0.1 6/0 (unsupported) 0 bytes `?

In my Router's loopback interface, I configure the following IP address: Router2(config-if)#ip address 2.0.3.2 255.255.255.255 Router2(config-if)# %BGP-3-NOTIFICATION: sent to neighbor 12.0.0.1 6/0 (...
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1answer
48 views

My BGP router does not advertise configured prefixes

I have two Routers, which are Router1(BGP 100) and Router2(BGP 200), they have set up BGP neighbor for each other: this is my Router1's BGP configuration: ! router bgp 100 bgp log-neighbor-changes ...
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1answer
78 views

Why Cisco BGP neighbor command need the remote-as number?

When I in my Router2 add a neighbor, the bellow is my command: Router2(config-router)#neighbor 12.0.0.1 remote-as 100 you see, I need write two params, one is neighbor address, and the other is its ...
4
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1answer
324 views

Advertise all static route except the default gateway with Juniper SRX firewall

With the following policy, all static routes are advertised via BGP to my neighbor: root@Nitrogen# show policy-options policy-statement bgp-export-policy { term export-statics { from ...
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1answer
35 views

Cisco create BGP connection, do we need two direction's neighbor command?

I have two routers like bellow: in the Router1, I configured like bellow: ! router bgp 100 bgp log-neighbor-changes no synchronization neighbor 12.0.0.2 remote-as 200 network 1.0.0.0 mask 255....
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3answers
101 views

Why can the BGP protocol be implemented across routers, but the OSPF protocol can only be implemented direct connected routers?

Why can the BGP protocol be implemented across routers? But the OSPF protocol can only be implemented on directly connected routers? Is the OSPF protocol based on IP? we know the BGP is based on ...
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1answer
40 views

Juniper router how to check the BGP process port?

Juniper router how to check the BGP process port? If I have a router with IP address 12.12.21.1, we know it run a BGP process, which use TCP 179 port as default. How can I check if port 179 is ...
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2answers
204 views

How to understand the output below from BGP?

I don't understand some data of the show route: admin@MX-RE0# run show route 36.250.236.6 inet.0: 736608 destinations, 806660 routes (736608 active, 0 holddown, 7 hidden) + = Active Route, - = Last ...
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1answer
303 views

Can non-recursive BGP route be used to determine next-hop for recursive BGP route?

In BGP recursive scenario, the recursive route is taking an unexpected next-hop. Here is the routing table: S* 0.0.0.0/0 [10/0] via 10.10.10.1, wan B 172.16.5.0/24 [20/0] via 172.80.80.1, MPLS, ...
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31 views

How to properly setup graceful-shutdown community

I'm trying to setup graceful-shutdown community but it looks I cannot make it working. community-set comm-graceful-shutdown 65535:0 end-set ! route-policy SOMEIX-IN ! tried set local-preference 0 ...
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1answer
183 views

Can two networks with the same subnet be connected to the same router in different VRF?

Let's say I have the following four networks: Network A: 10.0.1.0/24 Network B: 10.0.0.0/24 Network C: 10.0.1.0/24 Network D: 10.0.0.0/24 I would like to connect networks A and B together, and do ...
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3answers
2k views

Can I announce prefix 161.117.25.0/24 even though I don't have all of /24 IPs?

I'm managing one BGP router, under the router I'm trying to announce the following IP prefix:161.117.25.0/24. But the problem is that some of the IP addresses were borrowed by other AS(Autonomous ...
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1answer
35 views

Why does my route-map blackhole some equally specific routes? [closed]

I have a challenging situation. I have two routers, in VIRL, sharing routes via BGP and OSPF I am attempting to remove the "network 0.0.0.0 255.255.255.255 area 0" from my OSPF process. I have tried ...
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1answer
85 views

Connecting eBGP and iBGP routers in Quagga

I am trying to run intra and inter-domain routing using Quagga. I like to announce a prefix from AS7 and I like AS6 receive it and send it to AS2(as shown in the attached topology). I know for intra ...
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1answer
26 views

local pref question

i have a cisco router with 6 bgp peers, 4 bgp peers is from out ip transit's and i am receiving full routing (bgp) table from them. 2 bgp session is over GRE tunnel. and i am receiving 1.1.1.0/24 and ...
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1answer
122 views

How long the EBGP peer convergence time

We are using Anycast, and I plan to implement the "nearest access" by appending myself AS path to impact my peer BGP routers. For example I have two POPs(they are same ip), Pop1 in London and POP2 ...
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0answers
46 views

Understanding RIB and Update data from RouteViews

Can someone walk me through some RIB data from RouteViews? I'm having trouble understanding how to make sense of it. The main thing I need to figure out is what part of the RIB entry can be used to ...
3
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1answer
53 views

Explanation of repeated ASN in an AS path from a RouteViews file

From the RouteViews RIB files, I was looking at the snapshot from Nov 06, 2017 at 18:00 UTC. This has to do with this BGP routing misconfiguration -- https://dyn.com/blog/widespread-impact-caused-by-...