u*v
发帖数: 18 | 1 IBGP can not resend the BGP table from one IBGP neighor to other IBGP neighbor
, so you must be IBGP full mesh or using BGP reflector. You need not
physically connect these IBGP neighbor, BGP is using TCP, so just let the IBGP
nei can reach each other is enough, normally, you can run IGP for it. One
more thing, BGP will not install BGP into routing table and announce to other
AS, only if it syn with IGP or
you run IBGP on these nodes of the path to destination. |
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p**q
发帖数: 535 | 2 what does this mean?
"BGP requires that all iBGP speakers be fully meshed"
is it for physically fully meshed?
if there are 4 routers with connection like the following
A---B
| |
C---D
can i just configure all the other 3 as ibgp neighbors in each router to get
fully meshed? |
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p**q
发帖数: 535 | 3 thanks for zher and urv's answer.
i already have ospf between A B C D.
so physical fully mesh is not required. i will just need to add the ibgp
neighbor which
is not directly connected.
neighbor
IBGP
other |
|
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c*****i
发帖数: 631 | 5 customer as is same as sp. for small customers, they don't have their own AS
, so isp need to use other routing protocol like eigrp and ospf as ce-pe
protocol. with this new feature, they can use ibgp. |
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s**********9
发帖数: 1238 | 6
great!
那现在的15.0的IOS都支持PE-CE IBGP么？ |
|
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b******s
发帖数: 5329 | 8 对运营商而言，PE-CE用iBGP的优势在哪里？ |
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c******0
发帖数: 881 | 9 1. 单模多模光纤有啥特点，什么时候用哪一种？
2. 两台路由器直接用光纤口连，接口起不来，怎么办？
3. HSRP和GLBP是干什么的，有什么区别？
4. OSPF LSA type..
5. OSPF 邻居起不来,怎么办?
6. OSPF中一台路由器想把直连口加进来,除了在进程中起接口,还有什么方法?
答: redistribute connected
7. 这样redistribute进来的话,看到这个接口的网段是什么类型的LSA?
答: type 5
8. 还有没有别的办法加接口?
答: 接口下开启ospf进程
9. 如果不希望这个接口另外一边有人借此窃听到网络信息怎么办?
答: 加MD5验证
10. 还有没有别的办法?
答: passive interface
11. 什么是IBGP和EBGP?
12. 一般这两种邻居用什么接口建立关系?
答: IBGP -- loopback
EBGP -- 直连口
13. 为什么EBGP要用直连口连?
答: TTL值是1
14. 有什么办法可以用环回口?
答: multi-hop
15. IBGP和EBGP的防环方式?
答: Sp... 阅读全帖 |
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s*******8
发帖数: 12734 | 10 是pe-ce rip， pe-pe又有rip，又有mpls，还有ibgp，
我觉得pe-pe不需要rip了，如果有rip，干嘛还要ibgp，
如果rip和ibgp都在，那router怎么知道layer3用哪一个？再者，pe-router这个时候，
还需要redistribute么？ |
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c*****i
发帖数: 631 | 11 pe-pe的rip是igp。 ibgp是mp-ibgp,传mpls vpn route/ lable用的。当然如果你有
full mesh的ipv ibgp，就不需要rip的。
话说mpls support rip as igp吗。
上次还被人问了个TE需不需要mpls,汗阿。 |
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x*********n
发帖数: 28013 | 12 你要从头理解它。
AS本来就是一个virtual的concept，和area一样。
现在你几个location是一个company，你用什么iBGP还是eBGP？
iBGP require direct connection吗？为啥你config iBGP的时候不用改TTL？
后面的问题你应该都知道的，那就是自问自答了，呵呵。
再说RR，为什么要RR，是因为full mesh database大，那跟next-hop有什么关系？ |
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u*****e
发帖数: 47 | 13 最近刚开始接触juniper的产品，路由器，还真是跟cisco 有很多的不一样啊。搞得头
疼啊。。目前手上的资料也就只有juniper bgp configuration guide...着实压力不小
。经理又催着给配置文件（ibgp & ebgp，我们的网有点小复杂。。。）
1：
公司购买了/22的超网，但是在配置时，在路由器上还是划分成/25的小网段。现在要配
置BGP， 公司要求要把/22和/25都宣告出来。请问这个/22该怎么宣告呢？ 有点没想明
白该怎么宣告/22网段。毕竟不在机器上啊。。。
2：
在juniper上配BGP，关于宣告网段，是不是只能用bgp routing policy 去做。比如
inject OSPF ， 把直连导入BGP？对于ibgp 和ebgp, 这个导入的命令得做两次，对吧
？（记得cisco，只要宣告一次，ibgp和ebgp都可以用。） |
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s*****g
发帖数: 1055 | 14 Come on guys ... you always need IGP full-mesh iBGP or not, think about it,
iBGP relies on TCP, without IGP, how do you route BGP's TCP taffic?
"TE需不需要mpls", what kind of question is that? |
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z**r
发帖数: 17771 | 15 楼上chongqi已经解释的很清楚了。如果rip和ibgp都在同一个FIB里，当然是要选择rip
了，根据admistrator distance来判断。rip是120，ibgp是200.不过你的case不是这样
，建议看一下基本的mpls l3vpn的概念 |
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c*****i
发帖数: 631 | 16 我说的full-mesh ibgp是说core里面所有router都跑ibgp，不是说pe之间的full mesh。
"TE需不需要mpls"是问如果你要在一个core里面setup te，你需要config mpls吗。
, |
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f*******8
发帖数: 3612 | 17
,
问个问题，
iBGP router的作用是不是就是为了做distribution layer的default gateways?
ISP里根据什么需要选择一个router做iBGP? |
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x*********n
发帖数: 28013 | 18 PE-pE里面iBGP，如果iBGP里面有个link变化了，那么对整个MPLS有什么影响？
packet还按照LIB传么？router会drop这个packet么？
欢迎大家指点迷津。 |
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s*****g
发帖数: 1055 | 19 Don't you need IPv4 connectivity between iBGP peers (whether you use RR or
not is irreverent) ? 6PE will need MPLS transport LSP for iBGP peer IPv4
address. |
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x*********n
发帖数: 28013 | 20 谢谢大猫猫refer。
直白的问题就一个：
IBGP VS eBGP, why we need full mesh on iBGP
剩下的都是情景题。
RR, confederation,
at confederation, if sub-AS pass to another, sub-AS, will BGP attribute pass
or not?这个要我回答是or不是，我不太确定，就说sub AS的information应该是独立
的，不应该传给别人，他问我为啥这么想，我说传给别人了是不是要loop了啊?当时好
紧张，好混乱，寒风习习的，心那个凉啊。
router reflector, 2 group, 3 client, how packet goes from client1 to RR,
then RRA to RRB, then ....then what would happen, ( drop) what RRA do when
RRB send back, (Cluster-ID)基本上就是要我一步步的往哪里走，只有前面2步我貌似
走对了，他说correct，后... 阅读全帖 |
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s*****g
发帖数: 1055 | 21 Let me try to answer your questions, there are two types of MPLS VPNs, MPLS
L2VPN and MPLS L3VPN, MPLS L3VPN is standardized in well known RFC2547,
payload is IP, MPLS L2VPN is a general term for (Cisco)AToM, EoMPLS and
VPLS, payload is FR/HDLC but more commonly Ethernet/Ethernet VLAN.
ISPs need to run IGP in their own internal network, because MPLS LSPs are
typically among iBGP loopbacks, iBGP has to be on top of TCP/IP, of course
you can have MPLS LSPs that are purely used to transport IP tra... 阅读全帖 |
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b***p
发帖数: 700 | 22 I know what you mean. I thought LZ has other iBGP peers(R2) with the dual-
homing edge router(R1), in this case the router(R1) should withdraw/re-
advertise the prefixes from backup to iBGP peer(R2).
If LZ only has 1 BGP rtr as the edge, then no re-advertise, just best-select
the backup prefixes. |
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s*****g
发帖数: 1055 | 23 Technically I don't think there is a problem, but what for? we already have
LDP/RSVP, which rely on IGP to distribute transport labels, IBGP can not be
used as IGP. |
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w***s
发帖数: 321 | 24 iBGP session从哪儿到哪儿？
send- |
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s**********9
发帖数: 1238 | 25 最近面了一次，问了些RS基础问题，对方估计是个IE吧
我记的问了
2层 TRUNK,STP原理，状态
3层 OSPF AREA0作用，ABR,ASBR代表啥
BGP选路，MED, LOCALPREFENCE，同步原理，AS伪装，FULLMESH用在IBGP，BGP水平分割
。。。。
都是很基础的，不难 |
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s**********9
发帖数: 1238 | 26
interview
哦，就是AS内只传递EBGP路由，不再传递IBGP路由吧，是叫所谓的水平分割么？这些特
定术语我没记得那么清楚了，我知道那回事就是了。
呵呵，这个是纯猜测吧，我觉得他问的都是很理论的东西，反而实际工作的具体问题似
乎没怎么问。
我记得他问的问题都很讲究细节，有时候我表达不清楚，他还能提点我一下，让我正确
描述，总之给我感觉就是个TUTOR
我觉的如果没考过IE LAB的，可能工程经验会很足够，但对这些细节没那么讲究的
最近想跳槽，所以才去面了一下，刚好楼主问到，我就随便回忆了一下！ |
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s*****g
发帖数: 1055 | 27 This functionality is very useful from logical/design point of view for any
large customer networks. With this capability large customers can configure
their edge routers (CEs) the way as if those CEs are natively peered with
each other but in reality those CEs are actually peering with their
respective SP's PEs. |
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z**r
发帖数: 17771 | 28 so the customer AS will use the same AS that SP uses? or the SP will just
pretend to be the customer AS?
any
configure |
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j*a
发帖数: 14423 | 29 small customers can private AS
AS |
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z**r
发帖数: 17771 | 30 for small customers, why do they need to use BGP?
AS |
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|
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c*****i
发帖数: 631 | 33 another situantion is the CE is ISP's managed device. |
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z**r
发帖数: 17771 | 34 有道理，俺脑袋一拍又给想起一个，现在很多大企业的网络跟一个中小型SP差不多，各
种MPLS应用都有，他们倒是可以用 |
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s*******8
发帖数: 12734 | 35 ISP side，PE router上配RIPv2，MPLS,iBGP，一个口配vrf，
layer 3，就有2个routing protocol了，如果都配上，router会用哪个呢？还是不能都
配上？
Q2：我知道现实中不可能，实验环境下，如果一个boarder router，一边是rip，一边
是BGP，那么需要redistribute，如果我另一边再配一个rip，那么是不是不需要
redistribute了？
不好意思，小弟新人，问题有点傻，包涵。 |
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z**r
发帖数: 17771 | 36 你这表达的也太不清楚了，还得让人猜
你是问pe-ce是rip，pe-pe是mp-ibgp，然后之间怎么相互工作？ |
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s*****g
发帖数: 1055 | 37 So you are saying that if all core routers are running iBGP full mesh, then
you don't need IGP? Then we are talking about the same thing, and I am
telling you that you are wrong. ;-)
Of course you need to configure MPLS in the core (define configure MPLS?), TE can establish the LSP you want, but you still need MPLS functionality to switch the labeled packets.
Guys, guys, networking 102
mesh。 |
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s*******8
发帖数: 12734 | 38 是不是ibgp必须要有一个IGP在下面，才能运行啊？
或者，直接directly connect才行？ |
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d******t
发帖数: 834 | 39 PE-PE iBGP
PE-P-PE OSPF (接口开启MPLS)
PE-CE RIP V2
两个CE上分别用loopback口模拟192.168.1.0和10.1.1.0
路由表一切正常，两个CE可以看到对方的私有网段，ping不通，啥原因？ |
|
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c*****i
发帖数: 631 | 41 when ce is managed by isp |
|
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b******s
发帖数: 5329 | 43 not good point, even through CE is ISP managed, ISP still wants its core
separating with customer service access. And most of time, core team and
customer service team are two teams even under different VPs. |
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a***n
发帖数: 262 | 44 Hi All,
We are trying to deploy the 10G IPS at our campus. Attached please find the
simplified version of our network topology. All devices are standalone
catalyst 6500, and we currently have iBGP full mesh between core and
distribution. campus and resnet have different routing/security policy.
My question is where is the good place to place the IPS?
1) directly put them inline with our connection to our service provider. IPS
admins are not so confident about it even they have the fail-open har... 阅读全帖 |
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t*******r
发帖数: 3271 | 45 link就是link, 什么叫IBGP的link?
link断了, RSVP LSP重建, 重新分配mpls label.
业务断一小会儿, 没什么的.
frr开了的话, 断更小一会儿. |
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x*********n
发帖数: 28013 | 46 想来想去没想明白。
2个interface是这样的，用的是public IP
interface FastEthernet0/0
description **** MPLS data interface *****
ip address 10.99.32.1 255.255.255.128
ip pim sparse-dense-mode
duplex full
speed 100
!
interface FastEthernet0/1
description **** Voice interface *****
ip address 10.99.33.1 255.255.255.128
ip pim sparse-dense-mode
duplex full
speed 100
WAN IP，multilink出去。
interface Multilink1
ip address 65.112.128.118 255.255.255.252
ppp multilink
ppp multilink fragment disable
ppp multilink group 1
然后这2个... 阅读全帖 |
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s*****g
发帖数: 1055 | 47 Your multilink is for Internet access, the two Fast Ethernet interfaces are
connected to your MPLS-VPN service provider, you are running eBGP as PE-CE
routing protocol. You iBGP session over IPsec/GRE tunnel is for redundancy. |
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t*******r
发帖数: 3271 | 48 来自主题: EmergingNetworking版 - 求面试问题 Describe the series of events going on when the 4 Routers connected the
Ethernet power up the same time.
What fields are contained in OSPF’s HELLO Packets ? (10 40 seconds)
Desribe Hello Packets when two routers are in the 2WAY state (neighbor field
) …
Can a router with a higher priority pre-empt a DR or BDR ?
What does Priority 0 mean ?
Describe the various LSA types (1,2,3,4,5) and what they are used for ?
1. Explain the 1st line – what is is (NET)
2. What’s in the second line ? (LSP-ID)
Expl... 阅读全帖 |
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x*********n
发帖数: 28013 | 49 用 loopback 做router ID,如果AS都是65011，那不是ibgp么？
这个ebgp-multihop 20是啥意思呢？
router bgp 65011
no synchronization
bgp log-neighbor-changes
network 172.16.220.0 mask 255.255.255.0
neighbor 172.16.20.1 remote-as 65011
neighbor 172.16.20.1 ebgp-multihop 20
neighbor 172.16.20.1 update-source Loopback0
neighbor 172.16.20.3 remote-as 65011
neighbor 172.16.20.3 ebgp-multihop 20
neighbor 172.16.20.3 update-source Loopback0
neighbor 172.16.20.4 remote-as 65011
neighbor 172.16.20.4 ebgp-multihop 20
neighbor 172.16... 阅读全帖 |
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x*********n
发帖数: 28013 | 50 过几天发到版上来。
最可爱的是what is the difference between ibgp and ebgp?
我觉得吧，这种问题我entry level都直接答得上来，问NP level还是不太合适的，当
然了，也许还有玄机在里面，也许我entry level没有查知。
哈哈。 |
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