I have an application, which send periodically TCP/IP packets from a master to a slave with Time Sensitive Networking, which is implemented inside tc-taprio in Linux. Every manual tells me that I need to create a new virtual Network Interface with some VLAN ID. But actually I
Is there a way to create a virtual Interface with a VLAN ID set to 0? Or not to set a VLAN ID at all?
English wikipedia describes the VLAN ID 0 with: VLAN not set.
VLAN IDs 0x000 and 0xfff (0 and 4095) are reserved and cannot be used. Many implementations use VLID 0 for 'untagged'.
Related
I am working on insert vlan tags for some client macs on outgoing packets via native vlan. I have tried nh_hooks IN, OUT and Forward but didnt get any success.
What i want is either i can add tag to packet from client to native vlan and then send it via same vlan or is it possible that i can forward native vlan packet from some client based on MAC to tagged vlan interface?
Any suggestion in netlink code or kernel level code? or is it possible to do that via ebtables based on MAC?
VLAN tagging in Linux is accomplished by using subinterfaces, e.g. ip link add link eth0 name eth0.8 type vlan id 8 adds tagged VID 8 to eth0, creating the eth0.8 subinterface.
The native VLAN is the one that's not tagged on a trunk/port, so its VLAN ID elsewhere depends on whether and how the trunk endpoints (switches) tag the frames when forwarding.
On a VLAN trunk, the VID in the tag is the VLAN the frame is running in.
PC1 ---[SW1] ----[SW2] -----[SW3] ----PC3
[sw2] ---> PC2.
[sw2 also connect to PC2.
Assume SW2 is non-IEEE 802.1q switches that does not support VLAN. SW1, SW3 do support. All PC are in VLAN 10.
What the SW1/SW3 on the trunk port will send VLAN 10 packet as untagged packet so that PC2 can understand it. When SW1/SW3 receive any frame, it will classified it as VLAN 10.
The default native VLAN is VLAN 1.
1st mistake in question: native VLAN frame/packets are send and received untagged. (no 4 bytes VLAN header).
If I understand it correctly, To forward a native VLAN untagged to a tagged VLAN will be to configure SW1 native vlan to be VLAN 10 and SW3 native VLAN to Vlan 30. PC3 is in VLAN 30. The vlan 10 will get translated to VLAN 30.
So the vlan 10 in PC1 is the same as untagged frame in PC2 and vlan 30 in PC3.
I have a TCP based server application on Linux that uses AF_INET socket. I would like to tag all outgoing frames with a specific Vlan ID say 10. I tried the following:
creating a virtual interface eth0.10 and assigned it an IP address 192.168.0.1. I used the IP address to bind the socket using bind().
Binding the socket to the interface eth0.10 using setsockopt().
Even after trying the above ways, I was unable to see any vlan tagged tagged frames or frames with ethtype 0x8100 on wireshark.
Kindly suggest on how to tag packets without using raw sockets.
I am very new to Cisco networking (haven't done any course either). I have been trying to learn a bit of networking myself and had no trouble in doing some of the basic stuff which i needed for my personal work. But i am planning to buy a new Cisco switch(a gigabit switch) and configure it to 2 different networks (1 being an internet and other being a separate network for a specific job). I want to configure the ports in such a way that the first few slots for normal internet and the rest for my other network. For example if its a Cisco 2950 48 port switch, the first 1-16 port for my local internet network and the ports from 17-32 for my other network. Can somebody give me a run down on how to achieve this? Sorry for such a long but basic question, i am just trying to save few $$ and learning something new. Any help would be appreciated. Cheers
You can just create the 2 different Vlans and Give the Access port to the 1st vlan with port 1 - 16 , And for Second vlan Give access port remaining Ports. As well you can also configure 2 different network on Single Switch .
Vlans can separate the network traffic away from each other. For Example
Int range gi 0/1 - 16
Desc Local Internet Network
Switchport access vlan 444
Switch port mode access
Int range gi 0/17 - 32
Desc Other Network
Switchport access vlan 555
Switch port mode access
Of course it depends on what you plug into the ports? depends on what type of switchport it is going to be.
Switch#configure terminal
Switch(config)#vlan 10
Switch(config-vlan)#name Local_Internet_Network
Switch(config-vlan)#exit
Switch(config)#vlan 20
Switch(config-vlan)#name my_other_network
Switch(config-vlan)#exit
Switch(config)#interface range gigabitEthernet 0/1-16
Switch(config-if-range)#switchport mode access
Switch(config-if-range)#switchport access vlan 10
Switch(config-if-range)#exit
Switch(config)#interface range gigabitEthernet 0/17-32
Switch(config-if-range)#switchport mode access
Switch(config-if-range)#switchport access vlan 20
Switch(config-if-range)#exit
Switch(config)#exit
Switch#write memory
and check on trunk
The 2950 switch was a L2 switch only last time I checked so it will not be able to route between the VLANs. You may want to consider a small firewall in order to provide the layer 3 element (routing) and block any internet traffic from hitting your LAN. You can then also utilise a switch with this topology.
The respective switch VLANs for Internet and LAN would be connected to the relevant Internet /LAN firewall ports and your servers would be connected to the LAN. The switch management port should also be on the trusted LAN network or a dedicated management VLAN.
I have a laptop that is connected to my organization's network using one or more network adapters. I am trying to write a tool that will continuously monitor the connectivity status and connection quality of each network. However my networking knowledge to limited and the terminology confuses me.
Specifically finding all the network adapters. Someone suggested that I use the command ifconfig and it gave me what are called "interface identifiers".
ex:
['lo0', 'gif0', 'stf0', 'en0', 'en1', 'en2', 'bridge0', 'p2p0']
I'm not quite sure how this helps me solve my problem because I don't know what interface identifiers are and I am not sure how to leverage this information. My assumption is that they represent a computer or a router in the network.
If someone could clear this up or explain it to me in layman's terms that would be really helpful.
First of all, you need to understand that there may be physical network cards(OR/AND logical network adapters) present in the computer to identify connection/manage connection.
Next, you have an incorrect notion about interface identifier.
What you talked about(eth,virbr,lo) are interfaces. In IPv4 addressing scheme, we don't have interface ID. We have interface ID's in IPv6 addresses.
As mentioned in The Payoff of IPv6’s Very Large Address Size
In IPv4, IP addresses have no relationship to the addresses used for underlying data link layer network technologies. A host that connects to a TCP/IP network using an Ethernet network interface card (NIC) has an Ethernet MAC address and an IP address, but the two numbers are distinct and unrelated in any way.
With the overhaul of addressing in IPv6, an opportunity presented itself to create a better way of mapping IP unicast addresses and physical network addresses. Implementing this superior mapping technique was one of the reasons why IPv6 addresses were made so large. With 128 total bits, even with a full 48 bits reserved for network prefix and 16 bits for site subnet, we are still left with 64 bits to use for the interface identifier, which is analogous to the host ID under IPv4.
Having so many bits at our disposal gives us great flexibility. Instead of using arbitrary “made-up” identifiers for hosts, we can base the interface ID on the underlying data link layer hardware address, as long as that address is no greater than 64 bits in length. Since virtually all devices use layer two addresses of 64 bits or fewer, there is no problem in using those addresses for the interface identifier in IP addresses. This provides an immediate benefit: it makes networks easier to administer, since we don't have to record two arbitrary numbers for each host. The IP address can be derived from the MAC address and the network identifier. It also means we can in the future tell the IP address from the MAC address and vice-versa.
Visit this link for more clear understanding about interface ID.
Now,returning to clear your confusion,
all of the connections(interfaces) such as Ethernet-0,Ethernet-1,WiFi-1,etc. have their own interface identifier.You can think of them as a kind of special identification number which identifies the kind of interfaces available at that moment!
When you type ifconfig in Linux, it displays the status of the currently active interfaces.
Now,coming on the example part, let's say you have two Ethernet connections on your system, say, eth0 and eth1(these are interface names) ---so ifconfig will print these two as a result of it's output!
So,to identify these two separate interfaces,there must be an
interface identifier.The interface identifier(generally 64-bit) is
either automatically generated from the interface's MAC address using
the modified EUI-64 format, obtained from a DHCPv6 server,
automatically established randomly, or assigned manually.
Also,the interfaces which you have mentioned are some of the most-commonly used interfaces :-
'lo0', 'gif0', 'stf0', 'en0', 'en1', 'en2', 'bridge0', 'p2p0'
lo0---local network connection(0 for 1st connection of lan)
en0---ethernet connection(0,1,2 for 1st,2nd and 3rd connection on Ethernet)
bridge0---a bridged connection to this machine
p2p0---a peer-to-peer connection
don't know about gif,stf.Please note that there are logical connections/virtual connections,instead of limitation of physical connections(using NIC cards) too!
I discovered that there are man entries for gif and stf -- on OSX, at least. These are generic tunnel interface, and IPv6 to IPv4 tunnel interface ("Six To Four"), respectively.
What you have:
bond (bond0) interface (all modes except 4) with at least 2 ifaces (say eth0 / eth1) connected on the same external switch
bond0 interface joined on a software bridge (br0)
virtual machine (vm0) (eg LibVirt::LXC) with an interface on br0
What you get:
vm0 is not able to connect to (most) IP addresses via bond0 over br0
"bond0: received packet with own address as source address" in syslog
Why you get this:
When vm0 wants to contact an external IP address it will send out an ARP request. This L2 broadcast with the source mac of vm0 will leave through (depending on bonding mode) eg eth0, but via the external switch, re-enter through eth1 and thus bond0. Hence the switch br0 will learn the mac-address of vm0 on the port connected to bond0. As a consequence the ARP-reply is never received by vm0.
What can you do to resolve:
The reason I post this, next to sharing the info, is that I wasn't able to figure out a good enough solution. Those I did find are:
On vm0 set static ARP entry
Use bond0 mode=4 but your external switch must support this
Configure your external siwtch to use private VLAN on eth0/eth1 but only works in some use-cases and adds complexity
Add both physical interfaces to the bridge with spanning tree enabled, instead of using bond driver
Statically configuring the MAC of vm0 on the correct port of br0 is not an option on Linux (works on OpenBSD though)
I'm really hoping for a more elegant solution here... Anyone?
Thanks
I've got the same problem and I come up with the same analysis.
The only non-invasive/scalable solution I've found is to use the active/backup bonding (mode 1). The tradeoff is that you lose the aggregation.
IMO, the best solution is to use 802.3ad, but I can't always use it because I'm limited with 6 port-channels on most of my switches.
Try these options in bridge:
brigde_fd 0
bridge_stp off # switch on with more system like this
bridge_maxage 0
bridge_ageing 0
bridge_maxwait 0
Taken from this thread:
kvm bridge also in proxmox