In making payments through lightning channels, space is a factor that must be considered. However, one cannot tell how much capacity is available on which channel. Rusty Russell is proposing a change to the system that automatically attaches an ‘r’ field to any channel that has sufficient capacity to receive a certain amount. Some members of the community however think this may be risky because an unauthorized user can tell how much capacity one has and use it to attack.

A discussion started recently regarding the lack of channel capacity information in the Channel_announcement message.

channel_announcement is a gossip message in the Lightning protocol that contains information regarding the ownership of a channel. It links an on chain Bitcoin key to a Lightning node key. Currently the message does not include any information about the channel capacity, for which wallets have to search through the blockchain and that becomes tedious for mobile and light wallets, as they have to send a request to a block explorer API to get the capacity. Not having the capacity greatly decreases the routing success rates as you maybe trying to send 10 BTC through a channel that can handle a maximum of 1 BTC.