GRE Tunnels - Revision history

Dvdakker: /* Setting up (E)GRE-Tunnels Citylab and the Virtual Wall */

2021-08-11T12:07:18Z

Setting up (E)GRE-Tunnels Citylab and the Virtual Wall

← Older revision		Revision as of 12:07, 11 August 2021
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	If DHCP is used, the lower MTU should be advertised by the DHCP server.		If DHCP is used, the lower MTU should be advertised by the DHCP server.

	== Setting up ~~(E)GRE~~-Tunnels Citylab and the Virtual Wall ==		== Setting up EGRE-Tunnels Citylab and the Virtual Wall ==

	At this point it is not possible to set up 'multi-site' (e)GRE tunnels through the JFed interface, but it is possible to do so manually after the test has started. The process of doing so is very similar to manually creating EGRE-Tunnels within the citylab testbed itself, but the following caveats need to be taken into account:		At this point it is not possible to set up 'multi-site' (e)GRE tunnels through the JFed interface, but it is possible to do so manually after the test has started. The process of doing so is very similar to manually creating EGRE-Tunnels within the citylab testbed itself, but the following caveats need to be taken into account:

Dvdakker: /* Creating a link between three or more nodes */

2021-08-11T12:07:04Z

Creating a link between three or more nodes

← Older revision		Revision as of 12:07, 11 August 2021
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	The 3-node setup shown in the example on the right, with <code>citynode1</code> as a central node, can be created as follows:		The 3-node setup shown in the example on the right, with <code>citynode1</code> as a central node, can be created as follows:
	~~can be created as follows:~~

	#Run the `hostname` command on all three nodes to learn their fully qualified domain names.		#Run the `hostname` command on all three nodes to learn their fully qualified domain names.

Dvdakker: /* Creating a link between two nodes */

2021-08-11T12:06:19Z

Creating a link between two nodes

← Older revision		Revision as of 12:06, 11 August 2021
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	# Create the EGRE tunnel itself:		# Create the EGRE tunnel itself:
	#* On '''citynode1''' run: <code> sudo gre_add_tunnel -c 192.168.0.1/24 -m 1400 -6 link0 <fqdn_of_vwallnode1></code>		#* On '''citynode1''' run: <code> sudo gre_add_tunnel -c 192.168.0.1/24 -m 1400 -6 link0 <fqdn_of_vwallnode1></code>
	#* On '''vwallnode1''' run: <code> sudo gre_add_tunnel -c 192.168.0.1/24 -m 1400 -6 link0 <fqdn_of_citynode1></code>		#* On '''vwallnode1''' run: <code> sudo gre_add_tunnel -c 192.168.0.2/24 -m 1400 -6 link0 <fqdn_of_citynode1></code>

	The <code>gre_add_tunnel</code> commands shown above are very similar to the ones used to set up an EGRE-tunnel between citylab nodes, but there are a few important differences:		The <code>gre_add_tunnel</code> commands shown above are very similar to the ones used to set up an EGRE-tunnel between citylab nodes, but there are a few important differences:

Dvdakker: /* Creating a link between three or more nodes */

2021-08-11T12:06:00Z

Creating a link between three or more nodes

← Older revision		Revision as of 12:06, 11 August 2021
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	The 3-node setup shown in the example on the right, with <code>citynode1</code> as a central node, can be created as follows:		The 3-node setup shown in the example on the right, with <code>citynode1</code> as a central node, can be created as follows:
	can be created as follows:		can be created as follows:
	#Run the `hostname` command on all three nodes to learn their fully qualified domain names. ~~E.g:~~
	#* <code>~~citynode1~~.~~gretest~~.~~wall2~~-~~ilabt~~-~~iminds~~-be.~~lab.cityofthings.eu~~</code>		#Run the `hostname` command on all three nodes to learn their fully qualified domain names.
	#* <code>citynode2.~~gretest~~.~~wall2~~-~~ilabt~~-~~iminds-be.lab.cityofthings.eu~~</code>		#On '''citynode1''' run: <code>sudo gre_add_bridge -c 192.168.0.1/24 -m 1400 -6 link0 <fqdn_of_citynode2> <fdn_of_vwallnode1></code><br>The <code>gre_add_bridge</code> command used here is very similar to the one used to set up a multipoint GRE-link within the citylab testbed itself. Once again, the only differences are
	#* <code>~~vwallnode1~~.~~gretest~~.~~wall2~~-~~ilabt-iminds~~-be.~~wall2~~.~~ilabt.iminds~~.~~be</code>~~		#* The added <code>-m</code> flag to manually set the MTU on the created link (see [[#Creating_a_link_between_two_nodes_2\|this section]] as to why this is needed)
			#* The added <code>-6</code> flag to force the use of IPv6 (this is needed because the Virtual Wall testbed doesn't use public IPv4 addresses)
			#* The use of FQDNs rather than just hostnames to specify the other nodes to connect to.
			#Connect the other nodes to the 'GRE Bridge:
			#* On '''citynode2''' run: <code> sudo gre_add_tunnel -c 192.168.0.2/24 -m 1400 -6 link0 <fqdn_of_citynode1></code>
			#* On '''vwallnode1''' run: <code> sudo gre_add_tunnel -c 192.168.0.3/24 -m 1400 -6 link0 <fqdn_of_citynode1></code>

			Once the 'GRE Bridge' has been created it can be used just like any other linux bridge. Removing the 'GRE Bridge' is done in exactly the same way as it is done for a 'local' GRE Bridge. See [[#Creating_a_link_between_three_or_more_nodes\|this section]] for more information.

	== Setting up Link impairment on GRE Tunnels ==		== Setting up Link impairment on GRE Tunnels ==

Dvdakker: /* Creating a link between three or more nodes */

2021-08-11T10:35:50Z

Creating a link between three or more nodes

← Older revision		Revision as of 10:35, 11 August 2021
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	#Bridging all of these tunnels together to create a single shared subnet.		#Bridging all of these tunnels together to create a single shared subnet.

	When such an 'overlay subnet' spans multiple testbeds however, it is important to select the 'central node' very carefully. Consider for example the topology shown on the right. In this case a link is created to which two nodes of the citylab testbed and a single node of the virtual wall are connected. If, in this case, <code>vwallnode1</code> were to be selected as the 'central' node, then all traffic between <code>citynode1</code> and <code>citynode2</code> would be sent over the virtual wall testbed unnecessarily. ~~If on the other hand~~ <code>citynode1</code> or <code>citynode2</code> ~~is used~~ as a 'central' node, ~~then this problem is avoided~~.		When such an 'overlay subnet' spans multiple testbeds however, it is important to select the 'central node' very carefully. Consider for example the topology shown on the right. In this case a link is created to which two nodes of the citylab testbed and a single node of the virtual wall are connected. If, in this case, <code>vwallnode1</code> were to be selected as the 'central' node, then all traffic between <code>citynode1</code> and <code>citynode2</code> would be sent over the virtual wall testbed unnecessarily. While in this case it would therefore be better to use <code>citynode1</code> or <code>citynode2</code> as a central node, for other test-setups the 'central node' to use may not be so simple to determine.

			The 3-node setup shown in the example on the right, with <code>citynode1</code> as a central node, can be created as follows:
			can be created as follows:
			#Run the `hostname` command on all three nodes to learn their fully qualified domain names. E.g:
			#* <code>citynode1.gretest.wall2-ilabt-iminds-be.lab.cityofthings.eu</code>
			#* <code>citynode2.gretest.wall2-ilabt-iminds-be.lab.cityofthings.eu</code>
			#* <code>vwallnode1.gretest.wall2-ilabt-iminds-be.wall2.ilabt.iminds.be</code>

	== Setting up Link impairment on GRE Tunnels ==		== Setting up Link impairment on GRE Tunnels ==

Dvdakker: /* Creating a link between three or more nodes */

2021-08-11T10:33:52Z

Creating a link between three or more nodes

← Older revision		Revision as of 10:33, 11 August 2021
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	# On '''apu1''' run: <code>sudo gre_add_bridge -c 192.168.0.1/24 link0 apu2 apu3</code><br>As for the <code>gre_add_tunnel</code> script, <code>link0</code> is the name of the interface to create and the <code>-c</code> flag can optionally be used to configure an IPv4 address on the interface. The remaining parameters, in this case <code>apu2</code> and <code>apu3</code> are the hosts to connect to. The resolution of these hostnames to IP-addresses is done in exactly the same way as for the <code>gre_add_tunnel</code> script.		# On '''apu1''' run: <code>sudo gre_add_bridge -c 192.168.0.1/24 link0 apu2 apu3</code><br>As for the <code>gre_add_tunnel</code> script, <code>link0</code> is the name of the interface to create and the <code>-c</code> flag can optionally be used to configure an IPv4 address on the interface. The remaining parameters, in this case <code>apu2</code> and <code>apu3</code> are the hosts to connect to. The resolution of these hostnames to IP-addresses is done in exactly the same way as for the <code>gre_add_tunnel</code> script.
			#
	#* On '''apu2''' run: <code>sudo gre_add_tunnel -c 192.168.0.2/24 link0 apu1</code>		#* On '''apu2''' run: <code>sudo gre_add_tunnel -c 192.168.0.2/24 link0 apu1</code>
	#* On '''apu3''' run: <code>sudo gre_add_tunnel -c 192.168.0.3/24 link0 apu1</code>		#* On '''apu3''' run: <code>sudo gre_add_tunnel -c 192.168.0.3/24 link0 apu1</code>

Dvdakker: /* Creating a link between two nodes */

2021-08-11T10:28:19Z

Creating a link between two nodes

← Older revision		Revision as of 10:28, 11 August 2021
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	=== Creating a link between two nodes ===		=== Creating a link between two nodes ===
	[[File:Jfed-multisite-link-2-nodes.png\|thumb\|right\|A 'simple' multi-site link with two nodes.]]		[[File:Jfed-multisite-link-2-nodes.png\|thumb\|right\|A 'simple' multi-site link with two nodes. 'citynode1' is a node of the Citylab testbed. 'vwallnode1' is a node of the Virtual Wall testbed.]]
	A point-to-point (E)GRE tunnel can be created using the <code>gre_add_tunnel</code> script on both nodes.		A point-to-point (E)GRE tunnel can be created using the <code>gre_add_tunnel</code> script on both nodes.

Dvdakker: /* Creating a link between three or more nodes */

2021-08-11T10:27:33Z

Creating a link between three or more nodes

← Older revision		Revision as of 10:27, 11 August 2021
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	=== Creating a link between three or more nodes ===		=== Creating a link between three or more nodes ===
			[[File:Jfed-multisite-link-3-nodes.png\|right\|thumb\|A multi-site link with three nodes. 'citynode1' and 'citynode2' are Citylab nodes. 'vwallnode1' is a node on the Virtual Wall testbed.]]


	As with [[#Creating_a_link_between_three_or_more_nodes\|GRE links between citylab nodes]], setting up a GRE-link with more than two nodes is done by:		As with [[#Creating_a_link_between_three_or_more_nodes\|GRE links between citylab nodes]], setting up a GRE-link with more than two nodes is done by:

Dvdakker: /* Creating a link between two nodes */

2021-08-11T10:25:36Z

Creating a link between two nodes

← Older revision		Revision as of 10:25, 11 August 2021
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	=== Creating a link between two nodes ===		=== Creating a link between two nodes ===
			[[File:Jfed-multisite-link-2-nodes.png\|thumb\|right\|A 'simple' multi-site link with two nodes.]]
	A point-to-point (E)GRE tunnel can be created using the <code>gre_add_tunnel</code> script on both nodes.		A point-to-point (E)GRE tunnel can be created using the <code>gre_add_tunnel</code> script on both nodes.

Dvdakker: /* Creating a link between three or more nodes */

2021-08-11T10:23:03Z

Creating a link between three or more nodes

← Older revision		Revision as of 10:23, 11 August 2021
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	=== Creating a link between three or more nodes ===		=== Creating a link between three or more nodes ===

			As with [[#Creating_a_link_between_three_or_more_nodes\|GRE links between citylab nodes]], setting up a GRE-link with more than two nodes is done by:
			#Creating GRE tunnels from all nodes to a 'central' node
			#Bridging all of these tunnels together to create a single shared subnet.

			When such an 'overlay subnet' spans multiple testbeds however, it is important to select the 'central node' very carefully. Consider for example the topology shown on the right. In this case a link is created to which two nodes of the citylab testbed and a single node of the virtual wall are connected. If, in this case, <code>vwallnode1</code> were to be selected as the 'central' node, then all traffic between <code>citynode1</code> and <code>citynode2</code> would be sent over the virtual wall testbed unnecessarily. If on the other hand <code>citynode1</code> or <code>citynode2</code> is used as a 'central' node, then this problem is avoided.

	== Setting up Link impairment on GRE Tunnels ==		== Setting up Link impairment on GRE Tunnels ==