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juniper EX swuitch - rstp pt-to-pt

leblanc
leblanc asked
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I see several interfaces on my switches that are configured for rstp pt-to-pt. I understand that it is for specifying the full duplex. I also checked those interfaces and they are set as AUTO. Shouldn't it say FULL-DUPLEX? Also, the default is full duplex so we don't really need those commands. Correct? Thx
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Salah Eddine ELMRABETTechnical Lead Manager (Owner)

Commented:
Hi,

The command is not related for duplex configuration but for Spanning Tree Protocol, rstp stand for Rapid STP

The use of this command, is when you connect and non Edge node : Server, Computer... the command will make to switch bring the port UP in a fast way without waiting for STP negotiation.

This command is similar to Cisco command: switchport portfast!

For more details refer to the following link:

Example: Configuring Faster Convergence and Improving Network Stability with RSTP on EX-series Switches

Spanning-Tree Instance Interface Point-to-Point Link Mode

Understanding RSTP for EX Series Switches

Configuring Rapid Spanning-Tree Protocol

Regards.

Salah
leblancAccounting

Author

Commented:
Thanks for the info.
I understand the swotchport portfast command. But "The use of this command, is when you connect and non Edge node : Server, Computer..." So why do they use the pt-to-pt between the switches on the trunk ports in Example: Configuring Faster Convergence and Improving Network Stability with RSTP on EX-series Switches. Thx
Salah Eddine ELMRABETTechnical Lead Manager (Owner)

Commented:
Hi,

I didn't share the link for the specified scenario, but only to show the usage of the command!

I this scenario, there is a manual STP configuration with cost and interface specified instead of handling the STP automatically by the root bridge

Regards.

Salah
leblancAccounting

Author

Commented:
I am sorry but I am trying to understand the pt-to-pt. So if I understand correctly from your explanation, the RSTP point-to-point command is like the switchport portfast in Cisco. Cisco uses that command to bypass the STP reconvergence and it is usually used when it is connected to a PC or a server. Cisco does not use that command for the trunk. But from the Juniper example, it looks like they use that command between the switches trunks. That is what makes me confused.
Technical Lead Manager (Owner)
Commented:
Hi,

You are right, the point to point option of the RSTP MODE command stand for Full-Duplex ans shared argument stand for HALF-Duplex but not at the media level but in Spanning Tree level.

As per my understanding (without reading the link contents in deep) I guess it was standing for STP mode, but it's used for STP transition, see more details in page 25, 38 and 140 of this documents:

http://www.juniper.net/documentation/en_US/junos12.3/information-products/pathway-pages/ex-series/spanning-tree-protocols.pdf

Regards.

Salah