Cisco 300-410 - Implementing Cisco Enterprise Advanced Routing and Services (300-410 ENARSI)

The reason for the loop is that R2 is forwarding the packets destined to 10.1.1.1 to R4, instead of R1. This is because in the redistribute OSPF statement, BW metric has a higher value and delay has a value of 1. So, R2 chooses R4 over R1 for 10.1.1.0/24 subnet causing a loop. Now, R5 learns 10.1.1.0/24 from R3 and advertises the same route to R4, that R4 redistributes back in EIGRP. If R3 sets a tag of 1 while redistributing EIGRP in OSPF, and R4 denies all the OSPF routes with tag 1 while redistributing, it will not advertise 10.1.1.0/24 back into EIGRP. Hence, the loop will be broken.

after bgp session are UP.I configured the CoPP to drop 10.3.3.3 bgp traffic (R3).

R3 bgp traffic that matched the ACL 100 is dropped and the state is in IDLE

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access-list 100 permit tcp host 10.3.3.3 any eq bgp

access-list 100 permit tcp host 10.3.3.3 eq bgp any

!

class-map match-all class-bgp

match access-group 100

!

policy-map policy-bgp

class class-bgp

drop

!

control-plane

service-policy input policy-bgp

!

The 10.3.3.3 neighbor goes to IDLE

LDP multicasts hello messages to a well-known UDP port (646) in order to discover neighbors. Once the discovery is accomplished, a TCP connection (port 646) is established and the LDP session begins. LDP keepalives ensure the health of the session. Thanks to the LDP session, LDP messages create the label mappings required for a FEC. Withdraw messages are used when FECs need to be torn down.

vty 0:

+ cisco

+ 0csic

vty 1:

+ no username

+ no password

The command “aaa authentication login default none” means no authentication is required when

access to the device via Console/VTY/AUX so if one interface does not specify another login

authentication method (via the “login authentication …” command), it will allow to access

without requiring username or password. In this case VTY 1 does not specify another

authentication login method so it will use the default method (which is “none” in this case).

The ―summary-address‖ is only used to create aggregate addresses for OSPF at an autonomous system boundary. It means this command should only be used on the ASBR when you are trying to summarize externally redistributed routes from another protocol domain or you have a NSSA area. But a requirement to create a summarized route is:

―The ASBR compares the summary route’s range of addresses with all routes redistributed into OSPF on that ASBR to find any subordinate subnets (subnets that sit inside the summary route range). If at least one subordinate subnet exists, the ASBR advertises the summary route.‖

Command Default

Accounting port: 1813

Authentication port: 1812

Accounting: enabled

Authentication: enabled

Retransmission count: 1

Idle-time: 0

Server monitoring: disabled

Timeout: 5 seconds

Test username: test

Test password: test