In a CDP environment, what happens when the CDP interface on an adjacent device is configured without an IP address?
In a CDP environment, what happens when the CDP interface on an adjacent device is configured without an IP address?
In a Cisco Discovery Protocol (CDP) environment, CDP is a Layer 2 protocol that operates independently of IP addressing. If an adjacent device's interface is configured without an IP address, CDP will still operate normally. However, it will not be able to provide the IP address information for that neighbor, since there is no IP address assigned to the interface in question. Therefore, CDP can still provide other Layer 2 information about the neighbor but not the IP address.
I tested in Packet tracer and I don't see that CDP uses an IP address of another interface for the CDP neighbor, it just leaves it empty but still works as usual. I don't see how you guys say it is B, but the simulation on PT says otherwise. I'm going with C.
yeah tested in lab to, and the switch don't see other interface of my router
Packet tracer isn’t really reliable for something so in theory I believe it should be c
If B is true, cdp won't be a reliable network mapping utility. You wouldn't be able to map directly connected devices correctly if B is true.
unfortunately this is what happens, according to the cisco documentation (and GNS3 according to 4aynick), so we have to pay attention to the repeated IP addresses in the CDP "show" outputs.
Dude, I got confused with you here. You said Packet Tracer isn't reliable and therefore you disagree with his reasoning..... But then you agree with his answer. Lol wtf?
According to 4aynick who tested it through GNS3 and the CISCO documentation, answer B is correct, perhaps in Packet Tracer there is indeed this limitation, but it should include the ip address of another interface in an example of a #show cdp neighbors detail command, which does not happen leaving the ip address field empty (as I tested), but in GNS3 it manages to acquire the ip address of another interface (as mentioned by 4aynick), as well as also mentions the CISCO documentation, in this case, taking this into account limitation of Packet Tracer, I agree with answer B “updates the ip address of another interface”. https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/cdp/configuration/15-mt/cdp-15-mt-book/nm-cdp-discover.html#:~:text=Restrictions%20for%20Using%20Cisco%20Discovery%20Protocol,-Cisco%20Discovery%20Protocol&text=Cisco%20Discovery%20Protocol%20is%20not,the%20non%2DIP%20address%20interface
The Right answer is B. If a neighbor has no IP address on an interface enabled with Cisco Discovery Protocol, the IP address of another interface will be updated as IP address for the non-IP address interface. Reference: https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/cdp/configuration/15-mt/cdp-15-mt-book/nm-cdp-discover.html
What is the another interface? The C is correct. CDP does not need IPs to works normally https://learningnetwork.cisco.com/s/question/0D53i00000Kt3Mp/how-does-cdp-work-without-l3-addresses
Read his link! "If a neighbor has no IP address on an interface enabled with Cisco Discovery Protocol, the IP address of another interface will be updated as IP address for the non-IP address interface." B is correct, as stated by Gere.
When tested in the lab, the behaviour described in the link does not occur
It´s B
Answer is C. CDP Works on Layer 2 the Data Link layer and does not care if there is an IP configured or not. It will only list the IP address with show cdp neighbors detail command or show cdp interfaces or show cdp interface f0/0. The IP address field will be blank if no IP is assigned.
Thought it was C Researched and Read the question ....... its B...... CDP is a Layer 2, media-independent, and network-independent protocol that runs on Cisco devices and enables networking applications to learn about directly connected devices nearby2. If a neighbor has no IP address on an interface enabled with Cisco Discovery Protocol, the IP address of another interface will be updated as IP address for the non-IP address interface
https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/cdp/configuration/15-mt/cdp-15-mt-book/nm-cdp-discover.html in the 'Restrictions' paragraph.
Confirmed in my LAB. B is the answer.
C. It will only show info of the interface it's connected to, not another interface info like answer B. Other interface might be connected to something else.
https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/cdp/configuration/15-mt/cdp-15-mt-book/nm-cdp-discover.html
Restrictions for Using Cisco Discovery Protocol Cisco Discovery Protocol functions only on Cisco devices. Cisco Discovery Protocol is not supported on Frame Relay multipoint subinterfaces. If a neighbor has no IP address on an interface enabled with Cisco Discovery Protocol, the IP address of another interface will be updated as IP address for the non-IP address interface. https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/cdp/configuration/15-mt/cdp-15-mt-book/nm-cdp-discover.html#GUID-3C4F2637-ED36-4EC0-9CD5-B73C0CF9DBEC
C. CDP uses the IP address of another interface for that neighbor. If a neighbor has no IP address on an interface enabled with Cisco Discovery Protocol, the IP address of another interface will be updated as IP address for the non-IP address interface.
It is not B. Why majority picked B is beyond my networking comprehension. Cdp is a layer 2 protocol but can get ip info of an interface IF it has. Not picking the IP of another interface. Why would it even do that? To achieve what? This one i avoid the majority vote
Since there is no way to delete my previous comment, I withdraw my comment. This is directly from cisco site. “Restrictions” for Using Cisco Discovery Protocol Cisco Discovery Protocol functions only on Cisco devices. Cisco Discovery Protocol is not supported on Frame Relay multipoint subinterfaces. **If a neighbor has no IP address on an interface enabled with Cisco Discovery Protocol, the IP address of another interface will be updated as IP address for the non-IP address interface.*** So it’s a restriction of cdp. Correct answer is B
If a neighbor has no IP address on an interface enabled with Cisco Discovery Protocol, the IP address of another interface will be updated as IP address for the non-IP address interface. https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/cdp/configuration/15-mt/cdp-15-mt-book/nm-cdp-discover.html#GUID-3C4F2637-ED36-4EC0-9CD5-B73C0CF9DBEC
C is the correct answer
Restrictions for Using Cisco Discovery Protocol Cisco Discovery Protocol functions only on Cisco devices. Cisco Discovery Protocol is not supported on Frame Relay multipoint subinterfaces. If a neighbor has no IP address on an interface enabled with Cisco Discovery Protocol, the IP address of another interface will be updated as IP address for the non-IP address interface. https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/cdp/configuration/15-mt/cdp-15-mt-book/nm-cdp-discover.html
If cdp used ip, it wouldn't work on l2 switch
Answer is D lol, CDP operates normally, but it cannot provide IP address information for that neighbor - This answer is correct. When the CDP interface on an adjacent device is configured without an IP address, CDP will still operate normally, but it will not be able to provide any IP address information for that neighbor. https://www.exam-answer.com/cisco-200-301-ccna-cdp-environment-cdp-interface-adjacent-device-configured-without-ip-address#:~:text=Answer%20C%3A%20CDP%20operates%20normally,address%20information%20for%20that%20neighbor.
The answer is C. The question didn't mention that other interfaces have IP addresses, so we should assume that other ports are also not configured with IP addresses, unless IP addresses are automatically generated by default.