Hot answers tagged

6 votes
Accepted

Do Directly Connected Routers Need Routing Protocols For DHCP Relay To Work?

Routers need to know how to reach networks in order to send packets to those networks. DHCP relay is sending packets to other networks. Routers learn routes in three ways: Directly connected networks ...
Ron Maupin's user avatar
  • 99.4k
5 votes

Switches in chain topology for ~40 devices

Currently we have 6 switches chained together, Don't do that. Long chains, rings, double rings in switching require special (often proprietary) protocols instead of spanning-tree. Some of these sail ...
Marc 'netztier' Luethi's user avatar
5 votes

If all subnets are a part of same vlan, then the network segregation using subnets does not make sense

So, does Vlan and Subnetting go hand in hand? What I meant is, if we need to use subnetting, the do we need to also make sure each subnet is part of a different vlan? In 98% of the cases, YES. You ...
Ron Trunk's user avatar
  • 67.3k
5 votes
Accepted

What is PPP and why does it not have a MAC address?

PPP is a data link layer protocol that's designed to run on top of a simple serial link as physical layer. Since there are exactly two nodes on that point-to-point link, no addressing is required. The ...
Zac67's user avatar
  • 83.9k
4 votes

Finding what interface a MAC address is assigned to

That MAC address is assigned to PortChannel1. That is the Po1 in the result you got.
Ron Maupin's user avatar
  • 99.4k
4 votes
Accepted

Finding what interface a MAC address is assigned to

The |i(nclude) 5619 in your command filters the output to only display lines that contain 5619. That way, you won't see the table headers with Mac Address Table ------------------------------...
Zac67's user avatar
  • 83.9k
3 votes

Understanding the Role of Member Device in Cisco 3850 VSS Stack

You are correct. Switch number one is neither the active or the standby. If switch 3 were to fail, switch 1 would become the new standby.
Ron Trunk's user avatar
  • 67.3k
3 votes
Accepted

No access to internet via DHCP, but works with manual IPs

Ok, maybe this was a silly mistake, but in the DHCP server settings there was a field called "router" that I didn't know what it was, so I left it blank and forgot about it. This was the &...
Mike's user avatar
  • 133
3 votes
Accepted

Understanding Header Structure in Binary

The IETF settled on the network byte order to make sure that, regardless of the processor used in a host, the bytes on a network were consistently sent and received in the same order for use by the ...
Ron Maupin's user avatar
  • 99.4k
3 votes

Is there a difference between NetID and Network Address?

Your "gist" is wrong, unfortunately. "0"s and "255"s may or may not indicate anything. The important thing to remember is that IP addresses are 32-bit binary numbers. ...
Ron Trunk's user avatar
  • 67.3k
2 votes
Accepted

how do 2 different network communicate with each other

You are referring to the NAPT variant of NAT. In such a case, you must have NAPT port forwarding configured on the NAPT router. You cannot directly connect to a private address across the public ...
Ron Maupin's user avatar
  • 99.4k
2 votes

Finding what interface a MAC address is assigned to

To find the actual physical interface where that MAC address was learned, issue the command 'sh interfaces port-channel 1' or if you want to see a smaller output, 'sh interfaces port-channel 1 ...
FrameHowitzer's user avatar
2 votes
Accepted

Why No Ping When Use Static and RIP in This Network?

You are not actually running RIP since only one router is running RIP. RIP will exchange routing information with other RIP routers, but a single router running a routing protocol cannot exchange ...
Ron Maupin's user avatar
  • 99.4k
2 votes

How can GMPLS unify signalization plain of all telecommunications network technologies?

The idea of GMPLS is that it's hardware and media agnostic. Optical networks are just one kind of media that GMPLS can be used on.
Ron Trunk's user avatar
  • 67.3k
2 votes

Access multiple networks via one managed switch

That what VLANs are for. VLANs partition a physical switch (or a switching structure) into multiple, virtual switches. Devices on different VLANs cannot communicate with each other on the data link ...
Zac67's user avatar
  • 83.9k
2 votes

link between firewalls and cpe internet dedicated or on internal vlan

This borders on a opinion-based question but there are some objective facts. Arguably, the biggest security issue is that someone will enter the wrong command on the switch(es) and accidentally allow ...
Ron Trunk's user avatar
  • 67.3k
2 votes
Accepted

If all subnets are a part of same vlan, then the network segregation using subnets does not make sense

if all the subnets are part of the same Vlan, does the above advantage still make sense? Not really. If there's no L2 segregation by VLANs (or separate switches) then any host can join any subnet ...
Zac67's user avatar
  • 83.9k
2 votes
Accepted

Can wrong SFP module damage equipment?

No, not normally. By design, all SFP/SFP+/SFP28/... modules are electrically compatible. The maximum power-supply current defined by the SFF standards is 500 mA. All signal contacts are well defined ...
Zac67's user avatar
  • 83.9k
2 votes

Switches in chain topology for ~40 devices

An addition to Marc's totally valid answer: I am trying to justify why a different topology would be required for this network so that new equipment can be purchased. If there are no cabling/...
Zac67's user avatar
  • 83.9k
2 votes
Accepted

Understanding IPv4 model of operation

An IP packet (OSI layer 3) isn't encapsulated by another IP packet but by a data link layer frame (OSI layer 2). It is that frame that is addressed to the next-hop destination - either the gateway ...
Zac67's user avatar
  • 83.9k
2 votes
Accepted

How to interpret traceroute results?

I know that it displays the RTT of hops. Not exactly. ping and traceroute display the round-trip time for ICMP echo request and ICMP TTL expired in transit alone. The difference to actually used ...
Zac67's user avatar
  • 83.9k
2 votes
Accepted

Outgrowing a /24 network

You can use any subnet from the RFC 1918 ranges - 192.168.0.0/16, 172.16.0.0/12, 10.0.0.0/8 - with any subnetting, including 192.168.2.0/23, 10.111.220.0/22, and 172.16.24.0/21. I'd recommend using at ...
Zac67's user avatar
  • 83.9k
2 votes

Geolocation specific ASN

ASNs aren’t bound to a specific location, so what you’re asking is impossible to answer in general. Some large networks may use an ASN for a specific region, but if that’s the case you can only find ...
Teun Vink's user avatar
  • 17.1k
2 votes

TCP Header Data Field

The data is immediately after, not in, the TCP header; it is the TCP payload, which is application data. TCP segments and encapsulates application data into TCP PDUs that are called segments. IP, in ...
Ron Maupin's user avatar
  • 99.4k
2 votes
Accepted

TCP Duplicate Acknowledgement

A duplicate ACK is send when packets are received out of order which indicate that something is lost in between. In your scenario this will be: B receives 1 -> will ACK 1 B receives 3 (2 lost) -&...
Steffen Ullrich's user avatar
2 votes

Is there a difference between NetID and Network Address?

To answer the titular question... "Network Address" is a well defined term. (in many RFC's) NetID is not. The Network Address is the all-zeros address of a subnet. For a /24, that's a dot-...
Ricky's user avatar
  • 32.1k
1 vote

Simulating Network Infrastructure on GNS3: Switch Stacks and Configuration Challenges

Your choice for GNS3 seems to be not the best one, as others pointed out. It's just an emulator with a limited feature set. I wouldn't trust any results you'd get from that. If you cannot do this with ...
Teun Vink's user avatar
  • 17.1k
1 vote

Simulating Network Infrastructure on GNS3: Switch Stacks and Configuration Challenges

GNS3 is really a training/education tool. It's not a network simulator. Moreover, hardware features like stacking is very dependent on the exact hardware, and GNS3 only provides a rather generic ...
Ron Trunk's user avatar
  • 67.3k
1 vote

RIP v2 Network Command

Unless you include the no auto-summary command in the RIPv2 router process, RIPv2 will assume classful networks the way RIPv1 does. I have not seen either of those labs, but it seems that the Neil ...
Ron Maupin's user avatar
  • 99.4k
1 vote

Can wrong SFP module damage equipment?

So can wrong or incompatible SFP modules or cable damage the equipment itself, I've had that happen to me, but the problem was more mechanical than electrical. On a series of refurbished Cisco N3K-...
Marc 'netztier' Luethi's user avatar

Only top scored, non community-wiki answers of a minimum length are eligible