The ornamental design for a multi-port hub, as shown and described.
FIG. 1 is a front perspective view of a multi-port hub showing our new design;
FIG. 2 is rear perspective view thereof;
FIG. 3 is a top plan view thereof;
FIG. 4 is a bottom plan view thereof;
FIG. 5 is a left side elevational view thereof;
FIG. 6 is a right side elevational view thereof;
FIG. 7 is a front elevational view thereof; and,
FIG. 8 is a rear elevational view thereof.
The broken lines, showing all of the port and connector openings located on the rear of the article, depict environment that forms no part of the claimed design.