The meanings of SR、LRM、LR、ER and ZR

SR、LRM、LR、ER、ZR are terms used in fiber optic communications, stand for the transmission distance of the 10G modules.

SR stands for Short Range, these transceivers support link length of 300m over multi-mode fiber and use 850nm lasers.

LRM means Long Reach Multimode, these transceivers support distance up to 220m over multi-mode fiber and use 1310nm lasers.

LR means Long Reach, these transceivers support distance up to 10km over single mode fiber and use 1310nm lasers.

ER means Extended Reach, the data rate of these transceivers support distance up to 40km over single mode fiber and use 1550nm lasers.

ZR also stands for Extended Reach which can transmit 10G data rate and 80km distance over single mode fiber and use 1550nm lasers.

How to make Ubuntu as router for external traffic

Due to limitations in public IPs you cant give all your hosts the publicly route-able IPs. but on otherside you want to install packages etc on those private host . One way is to enable a Public IP with a Host (we called it as gateway host) which has two network card , One network card has public ip and other with private one.

Now you want to route all hosts in private network to route their public traffic via that (gateway) host .

On Gateway host do this:

## eth1 in above where you have public ip can be any interface

iptables -A FORWARD -i eth2 -j ACCEPT

## eth2 in above where you have private ip can be any interface

On Private hosts:

## 192.168.1.22 is our gateway’s private ip you can check with yours what is the private ip you have on gateway

## by running ifconfig eth2 ## replace eth2 with interface you have private ip on gateway